Apparatus for transmitting broadcast signals, apparatus for receiving broadcast signals, method for transmitting broadcast signals and method for receiving broadcast signals

ABSTRACT

A method and apparatus are presented for transmitting broadcast signals. Service data is encoded by an encoder. A signaling encoder encodes signaling data based on a mode of the signaling data. The signaling data is categorized to one of plural modes based on a modulation order for the signaling data. A frame builder builds at least one signal frame including the encoded service data in at least one data symbol and the encoded signaling data in at least one signaling symbol. A modulator modulates data in the at least one signal frame by an Orthogonal Frequency Division Multiplex (OFDM) scheme. A transmitter transmits the broadcast signals carrying the modulated data in the at least one signal frame. The broadcast signals further carry a bootstrap. The bootstrap includes category information indicating the mode of the signaling data in the at least one signaling symbol in the at least one signal frame.

CROSS REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims the benefit under 35 U.S.C.§119(e) to U.S. Provisional Application No. 62/097,565, filed on Dec.29, 2014, U.S. Provisional Application No. 62/110,597, filed on Feb. 1,2015, U.S. Provisional Application No. 62/113,504, filed on Feb. 8,2015, and U.S. Provisional Application No. 62/114,559 filed on Feb. 10,2015, all of which are hereby expressly incorporated by reference intothe present application.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an apparatus for transmitting broadcastsignals, an apparatus for receiving broadcast signals and methods fortransmitting and receiving broadcast signals.

Discussion of the Related Art

As analog broadcast signal transmission comes to an end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

That is, a digital broadcast system can provide HD (high definition)images, multi-channel audio and various additional services. However,data transmission efficiency for transmission of large amounts of data,robustness of transmission/reception networks and network flexibility inconsideration of mobile reception equipment need to be improved fordigital broadcast.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an apparatus fortransmitting broadcast signals and an apparatus for receiving broadcastsignals for future broadcast services and methods for transmitting andreceiving broadcast signals for future broadcast services.

An object of the present invention is to provide an apparatus and methodfor transmitting broadcast signals to multiplex data of a broadcasttransmission/reception system providing two or more different broadcastservices in a time domain and transmit the multiplexed data through thesame RF signal bandwidth and an apparatus and method for receivingbroadcast signals corresponding thereto.

Another object of the present invention is to provide an apparatus fortransmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals toclassify data corresponding to services by components, transmit datacorresponding to each component as a data pipe, receive and process thedata

Still another object of the present invention is to provide an apparatusfor transmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals tosignal signaling information necessary to provide broadcast signals.

Technical Solution

To achieve the object and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amethod for transmitting broadcast signals, the method comprises encodingservice data, encoding signaling data based on a mode of the signalingdata, wherein the signaling data is categorized to plural modes based ona length of the signaling data and modcod information, building at leastone signal frame including the encoded service data and the encodedsignaling data, modulating the at least one signal frame by an OFDM(Orthogonal Frequency Division Multiplex) scheme and transmitting thebroadcast signals carrying the at least one modulated signal frame.

Advantageous Effects

The present invention can process data according to servicecharacteristics to control QoS (Quality of Services) for each service orservice component, thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same RF signalbandwidth.

The present invention can improve data transmission efficiency andincrease robustness of transmission/reception of broadcast signals usinga MIMO system.

According to the present invention, it is possible to provide broadcastsignal transmission and reception methods and apparatus capable ofreceiving digital broadcast signals without error even with mobilereception equipment or in an indoor environment.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

FIG. 8 illustrates an OFMD generation block according to an embodimentof the present invention.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

FIG. 22 illustrates a Forward Error Correction (FEC) structure accordingto an embodiment of the present invention.

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

FIG. 26 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

FIG. 28 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

FIG. 29 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 30 illustrates a PLS data protection operation according to anembodiment of the present invention.

FIG. 31 illustrates the PLS scrambler according to the presentembodiment.

FIG. 32 illustrates a detailed operation of the parity interleavingblock using a PLS data structure.

FIG. 33 illustrates an operation of a bit-interleaving block of theapparatus for transmitting broadcast signals according to the presentembodiment.

FIG. 34 illustrates a detailed operation of a bit demultiplexer (demux)of the apparatus for transmitting broadcast signals according to thepresent embodiment.

FIG. 35 illustrates a result obtained by mapping bits input to theconstellation mapper onto the QAM symbol and outputting the mapped bitsby the constellation mapper according to the present embodiment.

FIG. 36 illustrates that PLS data decoding is performed in the apparatusfor receiving broadcast signals according to the present embodiment.

FIG. 37 illustrates a BICM block for protection of physical layersignaling (PLS), emergency alert channel (EAC) and fast informationchannel (FIC).

FIG. 38 illustrates input and output data of the bit interleaveraccording to the present embodiment.

FIG. 39 illustrates a configuration of a bit interleaver block of abroadcast signal transmission apparatus according to an embodiment ofthe present invention.

FIG. 40 shows an equation indicating an operation of a bit demultiplexerof a broadcast signal transmission apparatus according to an embodimentof the present invention.

FIG. 41 illustrates a bit deinterleaver of a broadcast signal receptionapparatus according to an embodiment of the present invention.

FIG. 42 shows an equation indicating an operation of a bit demultiplexerof a broadcast signal transmission apparatus according to an embodimentof the present invention.

FIG. 43 shows applicable ModCod combinations when PLS data signalingprotection according to an embodiment of the present invention isperformed.

FIGS. 44 to 46 are tables that categorize and show data according todata throughput.

FIG. 47 is a table showing BICM ModCod performance for each categoryaccording to an embodiment of the present invention.

FIG. 48 is a table showing BICM ModCod for each category according to anembodiment of the present invention.

FIG. 49 is a conceptual diagram illustrating a broadcast signaltransmission apparatus and a broadcast signal reception apparatusaccording to an embodiment of the present invention operating based onModCod information.

FIG. 50 illustrates a configuration of a decoding block of L1 signalingdata of a broadcast signal reception apparatus according to anembodiment of the present invention.

FIG. 51 is a flowchart illustrating a method of transmitting a broadcastsignal according to an embodiment of the present invention.

FIG. 52 is a flowchart illustrating a method of receiving a broadcastsignal according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although most terms used in the present invention have been selectedfrom general ones widely used in the art, some terms have beenarbitrarily selected by the applicant and their meanings are explainedin detail in the following description as needed. Thus, the presentinvention should be understood based upon the intended meanings of theterms rather than their simple names or meanings.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, aUHDTV service, etc. The present invention may process broadcast signalsfor the future broadcast services through non-MIMO (Multiple InputMultiple Output) or MIMO according to one embodiment. A non-MIMO schemeaccording to an embodiment of the present invention may include a MISO(Multiple Input Single Output) scheme, a SISO (Single Input SingleOutput) scheme, etc.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas.

The present invention may defines three physical layer (PL)profiles—base, handheld and advanced profiles—each optimized to minimizereceiver complexity while attaining the performance required for aparticular use case. The physical layer (PHY) profiles are subsets ofall configurations that a corresponding receiver should implement.

The three PHY profiles share most of the functional blocks but differslightly in specific blocks and/or parameters. Additional PHY profilescan be defined in the future. For the system evolution, future profilescan also be multiplexed with the existing profiles in a single RFchannel through a future extension frame (FEF). The details of each PHYprofile are described below.

1. Base Profile

The base profile represents a main use case for fixed receiving devicesthat are usually connected to a roof-top antenna. The base profile alsoincludes portable devices that could be transported to a place butbelong to a relatively stationary reception category. Use of the baseprofile could be extended to handheld devices or even vehicular by someimproved implementations, but those use cases are not expected for thebase profile receiver operation.

Target SNR range of reception is from approximately 10 to 20 dB, whichincludes the 15 dB SNR reception capability of the existing broadcastsystem (e.g. ATSC A/53). The receiver complexity and power consumptionis not as critical as in the battery-operated handheld devices, whichwill use the handheld profile. Key system parameters for the baseprofile are listed in below table 1.

TABLE 1 LDPC codeword length 16K, 64K bits Constellation size 4~10 bpcu(bits per channel use) Time de-interleaving memory size ≦2¹⁹ data cellsPilot patterns Pilot pattern for fixed reception FFT size 16K, 32Kpoints

2. Handheld Profile

The handheld profile is designed for use in handheld and vehiculardevices that operate with battery power. The devices can be moving withpedestrian or vehicle speed. The power consumption as well as thereceiver complexity is very important for the implementation of thedevices of the handheld profile. The target SNR range of the handheldprofile is approximately 0 to 10 dB, but can be configured to reachbelow 0 dB when intended for deeper indoor reception.

In addition to low SNR capability, resilience to the Doppler Effectcaused by receiver mobility is the most important performance attributeof the handheld profile. Key system parameters for the handheld profileare listed in the below table 2.

TABLE 2 LDPC codeword length 16K bits Constellation size 2~8 bpcu Timede-interleaving memory size ≦2¹⁸ data cells Pilot patterns Pilotpatterns for mobile and indoor reception FFT size 8K, 16K points

3. Advanced Profile

The advanced profile provides highest channel capacity at the cost ofmore implementation complexity. This profile requires using MIMOtransmission and reception, and UHDTV service is a target use case forwhich this profile is specifically designed. The increased capacity canalso be used to allow an increased number of services in a givenbandwidth, e.g., multiple SDTV or HDTV services.

The target SNR range of the advanced profile is approximately 20 to 30dB. MIMO transmission may initially use existing elliptically-polarizedtransmission equipment, with extension to full-power cross-polarizedtransmission in the future. Key system parameters for the advancedprofile are listed in below table 3.

TABLE 3 LDPC codeword length 16K, 64K bits Constellation size 8~12 bpcuTime de-interleaving memory size ≦2¹⁹ data cells Pilot patterns Pilotpattern for fixed reception FFT size 16K, 32K points

In this case, the base profile can be used as a profile for both theterrestrial broadcast service and the mobile broadcast service. That is,the base profile can be used to define a concept of a profile whichincludes the mobile profile. Also, the advanced profile can be dividedadvanced profile for a base profile with MIMO and advanced profile for ahandheld profile with MIMO. Moreover, the three profiles can be changedaccording to intention of the designer.

The following terms and definitions may apply to the present invention.The following terms and definitions can be changed according to design.

auxiliary stream: sequence of cells carrying data of as yet undefinedmodulation and coding, which may be used for future extensions or asrequired by broadcasters or network operators

base data pipe: data pipe that carries service signaling data

baseband frame (or BBFRAME): set of Kbch bits which form the input toone FEC encoding process (BCH and LDPC encoding)

cell: modulation value that is carried by one carrier of the OFDMtransmission

coded block: LDPC-encoded block of PLS1 data or one of the LDPC-encodedblocks of PLS2 data

data pipe: logical channel in the physical layer that carries servicedata or related metadata, which may carry one or multiple service(s) orservice component(s).

data pipe unit: a basic unit for allocating data cells to a DP in aframe.

data symbol: OFDM symbol in a frame which is not a preamble symbol (theframe signaling symbol and frame edge symbol is included in the datasymbol)

DP_ID: this 8-bit field identifies uniquely a DP within the systemidentified by the SYSTEM_ID

dummy cell: cell carrying a pseudo-random value used to fill theremaining capacity not used for PLS signaling, DPs or auxiliary streams

emergency alert channel: part of a frame that carries EAS informationdata

frame: physical layer time slot that starts with a preamble and endswith a frame edge symbol

frame repetition unit: a set of frames belonging to same or differentphysical layer profile including a FEF, which is repeated eight times ina super-frame

fast information channel: a logical channel in a frame that carries themapping information between a service and the corresponding base DP

FECBLOCK: set of LDPC-encoded bits of a DP data

FFT size: nominal FFT size used for a particular mode, equal to theactive symbol period Ts expressed in cycles of the elementary period T

frame signaling symbol: OFDM symbol with higher pilot density used atthe start of a frame in certain combinations of FFT size, guard intervaland scattered pilot pattern, which carries a part of the PLS data

frame edge symbol: OFDM symbol with higher pilot density used at the endof a frame in certain combinations of FFT size, guard interval andscattered pilot pattern

frame-group: the set of all the frames having the same PHY profile typein a super-frame.

future extension frame: physical layer time slot within the super-framethat could be used for future extension, which starts with a preamble

Futurecast UTB system: proposed physical layer broadcasting system, ofwhich the input is one or more MPEG2-TS or IP or general stream(s) andof which the output is an RF signal

input stream: A stream of data for an ensemble of services delivered tothe end users by the system.

normal data symbol: data symbol excluding the frame signaling symbol andthe frame edge symbol

PHY profile: subset of all configurations that a corresponding receivershould implement

PLS: physical layer signaling data consisting of PLS1 and PLS2

PLS1: a first set of PLS data carried in the FSS symbols having a fixedsize, coding and modulation, which carries basic information about thesystem as well as the parameters needed to decode the PLS2

NOTE: PLS1 data remains constant for the duration of a frame-group.

PLS2: a second set of PLS data transmitted in the FSS symbol, whichcarries more detailed PLS data about the system and the DPs

PLS2 dynamic data: PLS2 data that may dynamically change frame-by-frame

PLS2 static data: PLS2 data that remains static for the duration of aframe-group

preamble signaling data: signaling data carried by the preamble symboland used to identify the basic mode of the system

preamble symbol: fixed-length pilot symbol that carries basic PLS dataand is located in the beginning of a frame

NOTE: The preamble symbol is mainly used for fast initial band scan todetect the system signal, its timing, frequency offset, and FFT-size.

reserved for future use: not defined by the present document but may bedefined in future

super-frame: set of eight frame repetition units

time interleaving block (TI block): set of cells within which timeinterleaving is carried out, corresponding to one use of the timeinterleaver memory

TI group: unit over which dynamic capacity allocation for a particularDP is carried out, made up of an integer, dynamically varying number ofXFECBLOCKs

NOTE: The TI group may be mapped directly to one frame or may be mappedto multiple frames. It may contain one or more TI blocks.

Type 1 DP: DP of a frame where all DPs are mapped into the frame in TDMfashion

Type 2 DP: DP of a frame where all DPs are mapped into the frame in FDMfashion

XFECBLOCK: set of Ncells cells carrying all the bits of one LDPCFECBLOCK

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

The apparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can includean input formatting block 1000, a BICM (Bit interleaved coding &modulation) block 1010, a frame structure block 1020, an OFDM(Orthogonal Frequency Division Multiplexing) generation block 1030 and asignaling generation block 1040. A description will be given of theoperation of each module of the apparatus for transmitting broadcastsignals.

IP stream/packets and MPEG2-TS are the main input formats, other streamtypes are handled as General Streams. In addition to these data inputs,Management Information is input to control the scheduling and allocationof the corresponding bandwidth for each input stream. One or multiple TSstream(s), IP stream(s) and/or General Stream(s) inputs aresimultaneously allowed.

The input formatting block 1000 can demultiplex each input stream intoone or multiple data pipe(s), to each of which an independent coding andmodulation is applied. The data pipe (DP) is the basic unit forrobustness control, thereby affecting quality-of-service (QoS). One ormultiple service(s) or service component(s) can be carried by a singleDP. Details of operations of the input formatting block 1000 will bedescribed later.

The data pipe is a logical channel in the physical layer that carriesservice data or related metadata, which may carry one or multipleservice(s) or service component(s).

Also, the data pipe unit: a basic unit for allocating data cells to a DPin a frame.

In the BICM block 1010, parity data is added for error correction andthe encoded bit streams are mapped to complex-value constellationsymbols. The symbols are interleaved across a specific interleavingdepth that is used for the corresponding DP. For the advanced profile,MIMO encoding is performed in the BICM block 1010 and the additionaldata path is added at the output for MIMO transmission. Details ofoperations of the BICM block 1010 will be described later.

The Frame Building block 1020 can map the data cells of the input DPsinto the OFDM symbols within a frame. After mapping, the frequencyinterleaving is used for frequency-domain diversity, especially tocombat frequency-selective fading channels. Details of operations of theFrame Building block 1020 will be described later.

After inserting a preamble at the beginning of each frame, the OFDMGeneration block 1030 can apply conventional OFDM modulation having acyclic prefix as guard interval. For antenna space diversity, adistributed MISO scheme is applied across the transmitters. In addition,a Peak-to-Average Power Reduction (PAPR) scheme is performed in the timedomain. For flexible network planning, this proposal provides a set ofvarious FFT sizes, guard interval lengths and corresponding pilotpatterns. Details of operations of the OFDM Generation block 1030 willbe described later.

The Signaling Generation block 1040 can create physical layer signalinginformation used for the operation of each functional block. Thissignaling information is also transmitted so that the services ofinterest are properly recovered at the receiver side. Details ofoperations of the Signaling Generation block 1040 will be describedlater.

FIGS. 2, 3 and 4 illustrate the input formatting block 1000 according toembodiments of the present invention. A description will be given ofeach figure.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention. FIG. 2 shows an input formatting module whenthe input signal is a single input stream.

The input formatting block illustrated in FIG. 2 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

The input to the physical layer may be composed of one or multiple datastreams. Each data stream is carried by one DP. The mode adaptationmodules slice the incoming data stream into data fields of the basebandframe (BBF). The system supports three types of input data streams:MPEG2-TS, Internet protocol (IP) and Generic stream (GS). MPEG2-TS ischaracterized by fixed length (188 byte) packets with the first bytebeing a sync-byte (0x47). An IP stream is composed of variable length IPdatagram packets, as signaled within IP packet headers. The systemsupports both IPv4 and IPv6 for the IP stream. GS may be composed ofvariable length packets or constant length packets, signaled withinencapsulation packet headers.

(a) shows a mode adaptation block 2000 and a stream adaptation 2010 forsignal DP and (b) shows a PLS generation block 2020 and a PLS scrambler2030 for generating and processing PLS data. A description will be givenof the operation of each block.

The Input Stream Splitter splits the input TS, IP, GS streams intomultiple service or service component (audio, video, etc.) streams. Themode adaptation module 2010 is comprised of a CRC Encoder, BB (baseband)Frame Slicer, and BB Frame Header Insertion block.

The CRC Encoder provides three kinds of CRC encoding for error detectionat the user packet (UP) level, i.e., CRC-8, CRC-16, and CRC-32. Thecomputed CRC bytes are appended after the UP. CRC-8 is used for TSstream and CRC-32 for IP stream. If the GS stream doesn't provide theCRC encoding, the proposed CRC encoding should be applied.

BB Frame Slicer maps the input into an internal logical-bit format. Thefirst received bit is defined to be the MSB. The BB Frame Slicerallocates a number of input bits equal to the available data fieldcapacity. To allocate a number of input bits equal to the BBF payload,the UP packet stream is sliced to fit the data field of BBF.

BB Frame Header Insertion block can insert fixed length BBF header of 2bytes is inserted in front of the BB Frame. The BBF header is composedof STUFFI (1 bit), SYNCD (13 bits), and RFU (2 bits). In addition to thefixed 2-Byte BBF header, BBF can have an extension field (1 or 3 bytes)at the end of the 2-byte BBF header.

The stream adaptation 2010 is comprised of stuffing insertion block andBB scrambler.

The stuffing insertion block can insert stuffing field into a payload ofa BB frame. If the input data to the stream adaptation is sufficient tofill a BB-Frame, STUFFI is set to ‘0’ and the BBF has no stuffing field.Otherwise STUFFI is set to ‘1’ and the stuffing field is insertedimmediately after the BBF header. The stuffing field comprises two bytesof the stuffing field header and a variable size of stuffing data.

The BB scrambler scrambles complete BBF for energy dispersal. Thescrambling sequence is synchronous with the BBF. The scrambling sequenceis generated by the feed-back shift register.

The PLS generation block 2020 can generate physical layer signaling(PLS) data. The PLS provides the receiver with a means to accessphysical layer DPs. The PLS data consists of PLS1 data and PLS2 data.

The PLS1 data is a first set of PLS data carried in the FSS symbols inthe frame having a fixed size, coding and modulation, which carriesbasic information about the system as well as the parameters needed todecode the PLS2 data. The PLS1 data provides basic transmissionparameters including parameters required to enable the reception anddecoding of the PLS2 data. Also, the PLS1 data remains constant for theduration of a frame-group.

The PLS2 data is a second set of PLS data transmitted in the FSS symbol,which carries more detailed PLS data about the system and the DPs. ThePLS2 contains parameters that provide sufficient information for thereceiver to decode the desired DP. The PLS2 signaling further consistsof two types of parameters, PLS2 Static data (PLS2-STAT data) and PLS2dynamic data (PLS2-DYN data). The PLS2 Static data is PLS2 data thatremains static for the duration of a frame-group and the PLS2 dynamicdata is PLS2 data that may dynamically change frame-by-frame.

Details of the PLS data will be described later.

The PLS scrambler 2030 can scramble the generated PLS data for energydispersal.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 3 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 3 shows a mode adaptation block of the input formatting block whenthe input signal corresponds to multiple input streams.

The mode adaptation block of the input formatting block for processingthe multiple input streams can independently process the multiple inputstreams.

Referring to FIG. 3, the mode adaptation block for respectivelyprocessing the multiple input streams can include an input streamsplitter 3000, an input stream synchronizer 3010, a compensating delayblock 3020, a null packet deletion block 3030, a head compression block3040, a CRC encoder 3050, a BB frame slicer 3060 and a BB headerinsertion block 3070. Description will be given of each block of themode adaptation block.

Operations of the CRC encoder 3050, BB frame slicer 3060 and BB headerinsertion block 3070 correspond to those of the CRC encoder, BB frameslicer and BB header insertion block described with reference to FIG. 2and thus description thereof is omitted.

The input stream splitter 3000 can split the input TS, IP, GS streamsinto multiple service or service component (audio, video, etc.) streams.

The input stream synchronizer 3010 may be referred as ISSY. The ISSY canprovide suitable means to guarantee Constant Bit Rate (CBR) and constantend-to-end transmission delay for any input data format. The ISSY isalways used for the case of multiple DPs carrying TS, and optionallyused for multiple DPs carrying GS streams.

The compensating delay block 3020 can delay the split TS packet streamfollowing the insertion of ISSY information to allow a TS packetrecombining mechanism without requiring additional memory in thereceiver.

The null packet deletion block 3030, is used only for the TS inputstream case. Some TS input streams or split TS streams may have a largenumber of null-packets present in order to accommodate VBR (variablebit-rate) services in a CBR TS stream. In this case, in order to avoidunnecessary transmission overhead, null-packets can be identified andnot transmitted. In the receiver, removed null-packets can bere-inserted in the exact place where they were originally by referenceto a deleted null-packet (DNP) counter that is inserted in thetransmission, thus guaranteeing constant bit-rate and avoiding the needfor time-stamp (PCR) updating.

The head compression block 3040 can provide packet header compression toincrease transmission efficiency for TS or IP input streams. Because thereceiver can have a priori information on certain parts of the header,this known information can be deleted in the transmitter.

For Transport Stream, the receiver has a-priori information about thesync-byte configuration (0x47) and the packet length (188 Byte). If theinput TS stream carries content that has only one PID, i.e., for onlyone service component (video, audio, etc.) or service sub-component (SVCbase layer, SVC enhancement layer, MVC base view or MVC dependentviews), TS packet header compression can be applied (optionally) to theTransport Stream. IP packet header compression is used optionally if theinput steam is an IP stream.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 4 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 4 illustrates a stream adaptation block of the input formattingmodule when the input signal corresponds to multiple input streams.

Referring to FIG. 4, the mode adaptation block for respectivelyprocessing the multiple input streams can include a scheduler 4000, an1-Frame delay block 4010, a stuffing insertion block 4020, an in-bandsignaling 4030, a BB Frame scrambler 4040, a PLS generation block 4050and a PLS scrambler 4060. Description will be given of each block of thestream adaptation block.

Operations of the stuffing insertion block 4020, the BB Frame scrambler4040, the PLS generation block 4050 and the PLS scrambler 4060correspond to those of the stuffing insertion block, BB scrambler, PLSgeneration block and the PLS scrambler described with reference to FIG.2 and thus description thereof is omitted.

The scheduler 4000 can determine the overall cell allocation across theentire frame from the amount of FECBLOCKs of each DP. Including theallocation for PLS, EAC and FIC, the scheduler generate the values ofPLS2-DYN data, which is transmitted as in-band signaling or PLS cell inFSS of the frame. Details of FECBLOCK, EAC and FIC will be describedlater.

The 1-Frame delay block 4010 can delay the input data by onetransmission frame such that scheduling information about the next framecan be transmitted through the current frame for in-band signalinginformation to be inserted into the DPs.

The in-band signaling 4030 can insert un-delayed part of the PLS2 datainto a DP of a frame.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

The BICM block illustrated in FIG. 5 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

As described above, the apparatus for transmitting broadcast signals forfuture broadcast services according to an embodiment of the presentinvention can provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS (quality of service) depends on characteristics of a serviceprovided by the apparatus for transmitting broadcast signals for futurebroadcast services according to an embodiment of the present invention,data corresponding to respective services needs to be processed throughdifferent schemes. Accordingly, the a BICM block according to anembodiment of the present invention can independently process DPs inputthereto by independently applying SISO, MISO and MIMO schemes to thedata pipes respectively corresponding to data paths. Consequently, theapparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can controlQoS for each service or service component transmitted through each DP.

(a) shows the BICM block shared by the base profile and the handheldprofile and (b) shows the BICM block of the advanced profile.

The BICM block shared by the base profile and the handheld profile andthe BICM block of the advanced profile can include plural processingblocks for processing each DP.

A description will be given of each processing block of the BICM blockfor the base profile and the handheld profile and the BICM block for theadvanced profile.

A processing block 5000 of the BICM block for the base profile and thehandheld profile can include a Data FEC encoder 5010, a bit interleaver5020, a constellation mapper 5030, an SSD (Signal Space Diversity)encoding block 5040 and a time interleaver 5050.

The Data FEC encoder 5010 can perform the FEC encoding on the input BBFto generate FECBLOCK procedure using outer coding (BCH), and innercoding (LDPC). The outer coding (BCH) is optional coding method. Detailsof operations of the Data FEC encoder 5010 will be described later.

The bit interleaver 5020 can interleave outputs of the Data FEC encoder5010 to achieve optimized performance with combination of the LDPC codesand modulation scheme while providing an efficiently implementablestructure. Details of operations of the bit interleaver 5020 will bedescribed later.

The constellation mapper 5030 can modulate each cell word from the bitinterleaver 5020 in the base and the handheld profiles, or cell wordfrom the Cell-word demultiplexer 5010-1 in the advanced profile usingeither QPSK, QAM-16, non-uniform QAM (NUQ-64, NUQ-256, NUQ-1024) ornon-uniform constellation (NUC-16, NUC-64, NUC-256, NUC-1024) to give apower-normalized constellation point, e1. This constellation mapping isapplied only for DPs. Observe that QAM-16 and NUQs are square shaped,while NUCs have arbitrary shape. When each constellation is rotated byany multiple of 90 degrees, the rotated constellation exactly overlapswith its original one. This “rotation-sense” symmetric property makesthe capacities and the average powers of the real and imaginarycomponents equal to each other. Both NUQs and NUCs are definedspecifically for each code rate and the particular one used is signaledby the parameter DP_MOD filed in PLS2 data.

The SSD encoding block 5040 can precode cells in two (2D), three (3D),and four (4D) dimensions to increase the reception robustness underdifficult fading conditions.

The time interleaver 5050 can operates at the DP level. The parametersof time interleaving (TI) may be set differently for each DP. Details ofoperations of the time interleaver 5050 will be described later.

A processing block 5000-1 of the BICM block for the advanced profile caninclude the Data FEC encoder, bit interleaver, constellation mapper, andtime interleaver. However, the processing block 5000-1 is distinguishedfrom the processing block 5000 further includes a cell-worddemultiplexer 5010-1 and a MIMO encoding block 5020-1.

Also, the operations of the Data FEC encoder, bit interleaver,constellation mapper, and time interleaver in the processing block5000-1 correspond to those of the Data FEC encoder 5010, bit interleaver5020, constellation mapper 5030, and time interleaver 5050 described andthus description thereof is omitted.

The cell-word demultiplexer 5010-1 is used for the DP of the advancedprofile to divide the single cell-word stream into dual cell-wordstreams for MIMO processing. Details of operations of the cell-worddemultiplexer 5010-1 will be described later.

The MIMO encoding block 5020-1 can processing the output of thecell-word demultiplexer 5010-1 using MIMO encoding scheme. The MIMOencoding scheme was optimized for broadcasting signal transmission. TheMIMO technology is a promising way to get a capacity increase but itdepends on channel characteristics. Especially for broadcasting, thestrong LOS component of the channel or a difference in the receivedsignal power between two antennas caused by different signal propagationcharacteristics makes it difficult to get capacity gain from MIMO. Theproposed MIMO encoding scheme overcomes this problem using arotation-based pre-coding and phase randomization of one of the MIMOoutput signals.

MIMO encoding is intended for a 2×2 MIMO system requiring at least twoantennas at both the transmitter and the receiver. Two MIMO encodingmodes are defined in this proposal; full-rate spatial multiplexing(FR-SM) and full-rate full-diversity spatial multiplexing (FRFD-SM). TheFR-SM encoding provides capacity increase with relatively smallcomplexity increase at the receiver side while the FRFD-SM encodingprovides capacity increase and additional diversity gain with a greatcomplexity increase at the receiver side. The proposed MIMO encodingscheme has no restriction on the antenna polarity configuration.

MIMO processing is required for the advanced profile frame, which meansall DPs in the advanced profile frame are processed by the MIMO encoder.MIMO processing is applied at DP level. Pairs of the ConstellationMapper outputs NUQ (e1,i and e2,i) are fed to the input of the MIMOEncoder. Paired MIMO Encoder output (g1,i and g2,i) is transmitted bythe same carrier k and OFDM symbol 1 of their respective TX antennas.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

The BICM block illustrated in FIG. 6 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

FIG. 6 illustrates a BICM block for protection of physical layersignaling (PLS), emergency alert channel (EAC) and fast informationchannel (FIC). EAC is a part of a frame that carries EAS informationdata and FIC is a logical channel in a frame that carries the mappinginformation between a service and the corresponding base DP. Details ofthe EAC and FIC will be described later.

Referring to FIG. 6, the BICM block for protection of PLS, EAC and FICcan include a PLS FEC encoder 6000, a bit interleaver 6010 and aconstellation mapper 6020.

Also, the PLS FEC encoder 6000 can include a scrambler, BCHencoding/zero insertion block, LDPC encoding block and LDPC paritypuncturing block. Description will be given of each block of the BICMblock.

The PLS FEC encoder 6000 can encode the scrambled PLS 1/2 data, EAC andFIC section.

The scrambler can scramble PLS1 data and PLS2 data before BCH encodingand shortened and punctured LDPC encoding.

The BCH encoding/zero insertion block can perform outer encoding on thescrambled PLS 1/2 data using the shortened BCH code for PLS protectionand insert zero bits after the BCH encoding. For PLS1 data only, theoutput bits of the zero insertion may be permuted before LDPC encoding.

The LDPC encoding block can encode the output of the BCH encoding/zeroinsertion block using LDPC code. To generate a complete coded block,Cldpc, parity bits, Pldpc are encoded systematically from eachzero-inserted PLS information block, Ildpc and appended after it.C _(ldpc)=[I _(ldpc) P _(ldpc)]=[i ₀ ,i ₁ , . . . ,i _(K) _(ldpc) ⁻¹ ,p₀ ,p ₁ , . . . ,p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹]  [Math figure 1]

The LDPC code parameters for PLS1 and PLS2 are as following table 4.

TABLE 4 Signaling Type K_(sig) K_(bch) N_(bch) _(—) _(parity) K_(ldpc)(=N_(bch)) N_(ldpc) N_(ldpc) _(—) _(parity) code rate Q_(ldpc) PLS1 3421020 60 1080 4320 3240 1/4  36 PLS2 <1021 >1020 2100 2160 7200 5040 3/1056

The LDPC parity puncturing block can perform puncturing on the PLS1 dataand PLS 2 data.

When shortening is applied to the PLS1 data protection, some LDPC paritybits are punctured after LDPC encoding. Also, for the PLS2 dataprotection, the LDPC parity bits of PLS2 are punctured after LDPCencoding. These punctured bits are not transmitted.

The bit interleaver 6010 can interleave the each shortened and puncturedPLS1 data and PLS2 data.

The constellation mapper 6020 can map the bit interleaved PLS1 data andPLS2 data onto constellations.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

The frame building block illustrated in FIG. 7 corresponds to anembodiment of the frame building block 1020 described with reference toFIG. 1.

Referring to FIG. 7, the frame building block can include a delaycompensation block 7000, a cell mapper 7010 and a frequency interleaver7020. Description will be given of each block of the frame buildingblock.

The delay compensation block 7000 can adjust the timing between the datapipes and the corresponding PLS data to ensure that they are co-timed atthe transmitter end. The PLS data is delayed by the same amount as datapipes are by addressing the delays of data pipes caused by the InputFormatting block and BICM block. The delay of the BICM block is mainlydue to the time interleaver 5050. In-band signaling data carriesinformation of the next TI group so that they are carried one frameahead of the DPs to be signaled. The Delay Compensating block delaysin-band signaling data accordingly.

The cell mapper 7010 can map PLS, EAC, FIC, DPs, auxiliary streams anddummy cells into the active carriers of the OFDM symbols in the frame.The basic function of the cell mapper 7010 is to map data cells producedby the TIs for each of the DPs, PLS cells, and EAC/FIC cells, if any,into arrays of active OFDM cells corresponding to each of the OFDMsymbols within a frame. Service signaling data (such as PSI (programspecific information)/SI) can be separately gathered and sent by a datapipe. The Cell Mapper operates according to the dynamic informationproduced by the scheduler and the configuration of the frame structure.Details of the frame will be described later.

The frequency interleaver 7020 can randomly interleave data cellsreceived from the cell mapper 7010 to provide frequency diversity. Also,the frequency interleaver 7020 can operate on very OFDM symbol paircomprised of two sequential OFDM symbols using a differentinterleaving-seed order to get maximum interleaving gain in a singleframe.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 8 illustrates an OFMD generation block according to an embodimentof the present invention.

The OFMD generation block illustrated in FIG. 8 corresponds to anembodiment of the OFMD generation block 1030 described with reference toFIG. 1.

The OFDM generation block modulates the OFDM carriers by the cellsproduced by the Frame Building block, inserts the pilots, and producesthe time domain signal for transmission. Also, this block subsequentlyinserts guard intervals, and applies PAPR (Peak-to-Average Power Radio)reduction processing to produce the final RF signal.

Referring to FIG. 8, the frame building block can include a pilot andreserved tone insertion block 8000, a 2D-eSFN encoding block 8010, anIFFT (Inverse Fast Fourier Transform) block 8020, a PAPR reduction block8030, a guard interval insertion block 8040, a preamble insertion block8050, other system insertion block 8060 and a DAC block 8070.Description will be given of each block of the frame building block.

The pilot and reserved tone insertion block 8000 can insert pilots andthe reserved tone.

Various cells within the OFDM symbol are modulated with referenceinformation, known as pilots, which have transmitted values known apriori in the receiver. The information of pilot cells is made up ofscattered pilots, continual pilots, edge pilots, FSS (frame signalingsymbol) pilots and FES (frame edge symbol) pilots. Each pilot istransmitted at a particular boosted power level according to pilot typeand pilot pattern. The value of the pilot information is derived from areference sequence, which is a series of values, one for eachtransmitted carrier on any given symbol. The pilots can be used forframe synchronization, frequency synchronization, time synchronization,channel estimation, and transmission mode identification, and also canbe used to follow the phase noise.

Reference information, taken from the reference sequence, is transmittedin scattered pilot cells in every symbol except the preamble, FSS andFES of the frame. Continual pilots are inserted in every symbol of theframe. The number and location of continual pilots depends on both theFFT size and the scattered pilot pattern. The edge carriers are edgepilots in every symbol except for the preamble symbol. They are insertedin order to allow frequency interpolation up to the edge of thespectrum. FSS pilots are inserted in FSS(s) and FES pilots are insertedin FES. They are inserted in order to allow time interpolation up to theedge of the frame.

The system according to an embodiment of the present invention supportsthe SFN network, where distributed MISO scheme is optionally used tosupport very robust transmission mode. The 2D-eSFN is a distributed MISOscheme that uses multiple TX antennas, each of which is located in thedifferent transmitter site in the SFN network.

The 2D-eSFN encoding block 8010 can process a 2D-eSFN processing todistorts the phase of the signals transmitted from multipletransmitters, in order to create both time and frequency diversity inthe SFN configuration. Hence, burst errors due to low flat fading ordeep-fading for a long time can be mitigated.

The IFFT block 8020 can modulate the output from the 2D-eSFN encodingblock 8010 using OFDM modulation scheme. Any cell in the data symbolswhich has not been designated as a pilot (or as a reserved tone) carriesone of the data cells from the frequency interleaver. The cells aremapped to OFDM carriers.

The PAPR reduction block 8030 can perform a PAPR reduction on inputsignal using various PAPR reduction algorithm in the time domain.

The guard interval insertion block 8040 can insert guard intervals andthe preamble insertion block 8050 can insert preamble in front of thesignal. Details of a structure of the preamble will be described later.The other system insertion block 8060 can multiplex signals of aplurality of broadcast transmission/reception systems in the time domainsuch that data of two or more different broadcast transmission/receptionsystems providing broadcast services can be simultaneously transmittedin the same RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc. Datarelated to respective broadcast services can be transmitted throughdifferent frames.

The DAC block 8070 can convert an input digital signal into an analogsignal and output the analog signal. The signal output from the DACblock 7800 can be transmitted through multiple output antennas accordingto the physical layer profiles. A Tx antenna according to an embodimentof the present invention can have vertical or horizontal polarity.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention cancorrespond to the apparatus for transmitting broadcast signals forfuture broadcast services, described with reference to FIG. 1.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention can includea synchronization & demodulation module 9000, a frame parsing module9010, a demapping & decoding module 9020, an output processor 9030 and asignaling decoding module 9040. A description will be given of operationof each module of the apparatus for receiving broadcast signals.

The synchronization & demodulation module 9000 can receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the apparatus for receivingbroadcast signals and carry out demodulation corresponding to a reverseprocedure of the procedure performed by the apparatus for transmittingbroadcast signals.

The frame parsing module 9100 can parse input signal frames and extractdata through which a service selected by a user is transmitted. If theapparatus for transmitting broadcast signals performs interleaving, theframe parsing module 9100 can carry out deinterleaving corresponding toa reverse procedure of interleaving. In this case, the positions of asignal and data that need to be extracted can be obtained by decodingdata output from the signaling decoding module 9400 to restorescheduling information generated by the apparatus for transmittingbroadcast signals.

The demapping & decoding module 9200 can convert the input signals intobit domain data and then deinterleave the same as necessary. Thedemapping & decoding module 9200 can perform demapping for mappingapplied for transmission efficiency and correct an error generated on atransmission channel through decoding. In this case, the demapping &decoding module 9200 can obtain transmission parameters necessary fordemapping and decoding by decoding the data output from the signalingdecoding module 9400.

The output processor 9300 can perform reverse procedures of variouscompression/signal processing procedures which are applied by theapparatus for transmitting broadcast signals to improve transmissionefficiency. In this case, the output processor 9300 can acquirenecessary control information from data output from the signalingdecoding module 9400. The output of the output processor 8300corresponds to a signal input to the apparatus for transmittingbroadcast signals and may be MPEG-TSs, IP streams (v4 or v6) and genericstreams.

The signaling decoding module 9400 can obtain PLS information from thesignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9100, demapping & decodingmodule 9200 and output processor 9300 can execute functions thereofusing the data output from the signaling decoding module 9400.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 10 shows an example configuration of the frame types and FRUs in asuper-frame. (a) shows a super frame according to an embodiment of thepresent invention, (b) shows FRU (Frame Repetition Unit) according to anembodiment of the present invention, (c) shows frames of variable PHYprofiles in the FRU and (d) shows a structure of a frame.

A super-frame may be composed of eight FRUs. The FRU is a basicmultiplexing unit for TDM of the frames, and is repeated eight times ina super-frame.

Each frame in the FRU belongs to one of the PHY profiles, (base,handheld, advanced) or FEF. The maximum allowed number of the frames inthe FRU is four and a given PHY profile can appear any number of timesfrom zero times to four times in the FRU (e.g., base, base, handheld,advanced). PHY profile definitions can be extended using reserved valuesof the PHY_PROFILE in the preamble, if required.

The FEF part is inserted at the end of the FRU, if included. When theFEF is included in the FRU, the minimum number of FEFs is 8 in asuper-frame. It is not recommended that FEF parts be adjacent to eachother.

One frame is further divided into a number of OFDM symbols and apreamble. As shown in (d), the frame comprises a preamble, one or moreframe signaling symbols (FSS), normal data symbols and a frame edgesymbol (FES).

The preamble is a special symbol that enables fast Futurecast UTB systemsignal detection and provides a set of basic transmission parameters forefficient transmission and reception of the signal. The detaileddescription of the preamble will be will be described later.

The main purpose of the FSS(s) is to carry the PLS data. For fastsynchronization and channel estimation, and hence fast decoding of PLSdata, the FSS has more dense pilot pattern than the normal data symbol.The FES has exactly the same pilots as the FSS, which enablesfrequency-only interpolation within the FES and temporal interpolation,without extrapolation, for symbols immediately preceding the FES.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 11 illustrates the signaling hierarchy structure, which is splitinto three main parts: the preamble signaling data 11000, the PLS1 data11010 and the PLS2 data 11020. The purpose of the preamble, which iscarried by the preamble symbol in every frame, is to indicate thetransmission type and basic transmission parameters of that frame. ThePLS1 enables the receiver to access and decode the PLS2 data, whichcontains the parameters to access the DP of interest. The PLS2 iscarried in every frame and split into two main parts: PLS2-STAT data andPLS2-DYN data. The static and dynamic portion of PLS2 data is followedby padding, if necessary.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

Preamble signaling data carries 21 bits of information that are neededto enable the receiver to access PLS data and trace DPs within the framestructure. Details of the preamble signaling data are as follows:

PHY_PROFILE: This 3-bit field indicates the PHY profile type of thecurrent frame. The mapping of different PHY profile types is given inbelow table 5.

TABLE 5 Value PHY profile 000 Base profile 001 Handheld profile 010Advanced profiled 011~110 Reserved 111 FEF

FFT_SIZE: This 2 bit field indicates the FFT size of the current framewithin a frame-group, as described in below table 6.

TABLE 6 Value FFT size 00  8K FFT 01 16K FFT 10 32K FFT 11 Reserved

GI_FRACTION: This 3 bit field indicates the guard interval fractionvalue in the current super-frame, as described in below table 7.

TABLE 7 Value GI_FRACTION 000 ⅕ 001 1/10 010 1/20 011 1/40 100 1/80 1011/160 110~111 Reserved

EAC_FLAG: This 1 bit field indicates whether the EAC is provided in thecurrent frame. If this field is set to ‘1’, emergency alert service(EAS) is provided in the current frame. If this field set to ‘0’, EAS isnot carried in the current frame. This field can be switched dynamicallywithin a super-frame.

PILOT_MODE: This 1-bit field indicates whether the pilot mode is mobilemode or fixed mode for the current frame in the current frame-group. Ifthis field is set to ‘0’, mobile pilot mode is used. If the field is setto ‘1’, the fixed pilot mode is used.

PAPR_FLAG: This 1-bit field indicates whether PAPR reduction is used forthe current frame in the current frame-group. If this field is set tovalue ‘1’, tone reservation is used for PAPR reduction. If this field isset to ‘0’, PAPR reduction is not used.

FRU_CONFIGURE: This 3-bit field indicates the PHY profile typeconfigurations of the frame repetition units (FRU) that are present inthe current super-frame. All profile types conveyed in the currentsuper-frame are identified in this field in all preambles in the currentsuper-frame. The 3-bit field has a different definition for eachprofile, as show in below table 8.

TABLE 8 Current Current Current PHY_PROFILE = PHY_PROFILE = CurrentPHY_PROFILE = ‘001’ ‘010’ PHY_PROFILE = ‘000’ (base) (handheld)(advanced) ‘111’ (FEF) FRU_CONFIGURE = Only base Only handheld Onlyadvanced Only FEF 000 profile profile present profile present presentpresent FRU_CONFIGURE = Handheld Base profile Base profile Base profile1XX profile present present present present FRU_CONFIGURE = AdvancedAdvanced Handheld Handheld profile X1X profile profile profile presentpresent present present FRU_CONFIGURE = FEF FEF FEF Advanced profile XX1present present present present

RESERVED: This 7-bit field is reserved for future use.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

PLS1 data provides basic transmission parameters including parametersrequired to enable the reception and decoding of the PLS2. As abovementioned, the PLS1 data remain unchanged for the entire duration of oneframe-group. The detailed definition of the signaling fields of the PLS1data are as follows:

PREAMBLE_DATA: This 20-bit field is a copy of the preamble signalingdata excluding the EAC_FLAG.

NUM_FRAME_FRU: This 2-bit field indicates the number of the frames perFRU.

PAYLOAD_TYPE: This 3-bit field indicates the format of the payload datacarried in the frame-group. PAYLOAD_TYPE is signaled as shown in table9.

TABLE 9 value Payload type 1XX TS stream is transmitted X1X IP stream istransmitted XX1 GS stream is transmitted

NUM_FSS: This 2-bit field indicates the number of FSS symbols in thecurrent frame.

SYSTEM_VERSION: This 8-bit field indicates the version of thetransmitted signal format. The SYSTEM_VERSION is divided into two 4-bitfields, which are a major version and a minor version.

Major version: The MSB four bits of SYSTEM_VERSION field indicate majorversion information. A change in the major version field indicates anon-backward-compatible change. The default value is ‘0000’. For theversion described in this standard, the value is set to ‘0000’.

Minor version: The LSB four bits of SYSTEM_VERSION field indicate minorversion information. A change in the minor version field isbackward-compatible.

CELL_ID: This is a 16-bit field which uniquely identifies a geographiccell in an ATSC network. An ATSC cell coverage area may consist of oneor more frequencies, depending on the number of frequencies used perFuturecast UTB system. If the value of the CELL_ID is not known orunspecified, this field is set to ‘0’.

NETWORK_ID: This is a 16-bit field which uniquely identifies the currentATSC network.

SYSTEM_ID: This 16-bit field uniquely identifies the Futurecast UTBsystem within the ATSC network. The Futurecast UTB system is theterrestrial broadcast system whose input is one or more input streams(TS, IP, GS) and whose output is an RF signal. The Futurecast UTB systemcarries one or more PHY profiles and FEF, if any. The same FuturecastUTB system may carry different input streams and use different RFfrequencies in different geographical areas, allowing local serviceinsertion. The frame structure and scheduling is controlled in one placeand is identical for all transmissions within a Futurecast UTB system.One or more Futurecast UTB systems may have the same SYSTEM_ID meaningthat they all have the same physical layer structure and configuration.

The following loop consists of FRU_PHY_PROFILE, FRU_FRAME_LENGTH,FRU_GI_FRACTION, and RESERVED which are used to indicate the FRUconfiguration and the length of each frame type. The loop size is fixedso that four PHY profiles (including a FEF) are signaled within the FRU.If NUM_FRAME_FRU is less than 4, the unused fields are filled withzeros.

FRU_PHY_PROFILE: This 3-bit field indicates the PHY profile type of the(i+1)th (i is the loop index) frame of the associated FRU. This fielduses the same signaling format as shown in the table 8.

FRU_FRAME_LENGTH: This 2-bit field indicates the length of the (i+1)thframe of the associated FRU. Using FRU_FRAME_LENGTH together withFRU_GI_FRACTION, the exact value of the frame duration can be obtained.

FRU_GI_FRACTION: This 3-bit field indicates the guard interval fractionvalue of the (i+1)th frame of the associated FRU. FRU_GI_FRACTION issignaled according to the table 7.

RESERVED: This 4-bit field is reserved for future use.

The following fields provide parameters for decoding the PLS2 data.

PLS2_FEC_TYPE: This 2-bit field indicates the FEC type used by the PLS2protection. The FEC type is signaled according to table 10. The detailsof the LDPC codes will be described later.

TABLE 10 Content PLS2 FEC type 00 4K-1/4 and 7K-3/10 LDPC codes 01~11Reserved

PLS2_MOD: This 3-bit field indicates the modulation type used by thePLS2. The modulation type is signaled according to table 11.

TABLE 11 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16 011 NUQ-64 100~111Reserved

PLS2_SIZE_CELL: This 15-bit field indicates Ctotal_partial_block, thesize (specified as the number of QAM cells) of the collection of fullcoded blocks for PLS2 that is carried in the current frame-group. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_STAT_SIZE_BIT: This 14-bit field indicates the size, in bits, ofthe PLS2-STAT for the current frame-group. This value is constant duringthe entire duration of the current frame-group.

PLS2_DYN_SIZE_BIT: This 14-bit field indicates the size, in bits, of thePLS2-DYN for the current frame-group. This value is constant during theentire duration of the current frame-group.

PLS2_REP_FLAG: This 1-bit flag indicates whether the PLS2 repetitionmode is used in the current frame-group. When this field is set to value‘1’, the PLS2 repetition mode is activated. When this field is set tovalue ‘0’, the PLS2 repetition mode is deactivated.

PLS2_REP_SIZE_CELL: This 15-bit field indicates Ctotal_partial_block,the size (specified as the number of QAM cells) of the collection ofpartial coded blocks for PLS2 carried in every frame of the currentframe-group, when PLS2 repetition is used. If repetition is not used,the value of this field is equal to 0. This value is constant during theentire duration of the current frame-group.

PLS2_NEXT_FEC_TYPE: This 2-bit field indicates the FEC type used forPLS2 that is carried in every frame of the next frame-group. The FECtype is signaled according to the table 10.

PLS2_NEXT_MOD: This 3-bit field indicates the modulation type used forPLS2 that is carried in every frame of the next frame-group. Themodulation type is signaled according to the table 11.

PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the PLS2repetition mode is used in the next frame-group. When this field is setto value ‘1’, the PLS2 repetition mode is activated. When this field isset to value ‘0’, the PLS2 repetition mode is deactivated.

PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicates Ctotal_full_block,The size (specified as the number of QAM cells) of the collection offull coded blocks for PLS2 that is carried in every frame of the nextframe-group, when PLS2 repetition is used. If repetition is not used inthe next frame-group, the value of this field is equal to 0. This valueis constant during the entire duration of the current frame-group.

PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-STAT for the next frame-group. This value is constantin the current frame-group.

PLS2_NEXT_REP_DYN_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-DYN for the next frame-group. This value is constantin the current frame-group.

PLS2_AP_MODE: This 2-bit field indicates whether additional parity isprovided for PLS2 in the current frame-group. This value is constantduring the entire duration of the current frame-group. The below table12 gives the values of this field. When this field is set to ‘00’,additional parity is not used for the PLS2 in the current frame-group.

TABLE 12 Value PLS2-AP mode 00 AP is not provided 01 AP1 mode 10~11Reserved

PLS2_AP_SIZE_CELL: This 15-bit field indicates the size (specified asthe number of QAM cells) of the additional parity bits of the PLS2. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_AP_MODE: This 2-bit field indicates whether additional parityis provided for PLS2 signaling in every frame of next frame-group. Thisvalue is constant during the entire duration of the current frame-group.The table 12 defines the values of this field

PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates the size (specifiedas the number of QAM cells) of the additional parity bits of the PLS2 inevery frame of the next frame-group. This value is constant during theentire duration of the current frame-group.

RESERVED: This 32-bit field is reserved for future use.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS1 signaling.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2-STAT data of the PLS2 data. The PLS2-STAT dataare the same within a frame-group, while the PLS2-DYN data provideinformation that is specific for the current frame.

The details of fields of the PLS2-STAT data are as follows:

FIC_FLAG: This 1-bit field indicates whether the FIC is used in thecurrent frame-group. If this field is set to ‘1’, the FIC is provided inthe current frame. If this field set to ‘0’, the FIC is not carried inthe current frame. This value is constant during the entire duration ofthe current frame-group.

AUX_FLAG: This 1-bit field indicates whether the auxiliary stream(s) isused in the current frame-group. If this field is set to ‘1’, theauxiliary stream is provided in the current frame. If this field set to‘0’, the auxiliary stream is not carried in the current frame. Thisvalue is constant during the entire duration of current frame-group.

NUM_DP: This 6-bit field indicates the number of DPs carried within thecurrent frame. The value of this field ranges from 1 to 64, and thenumber of DPs is NUM_DP+1.

DP_ID: This 6-bit field identifies uniquely a DP within a PHY profile.

DP_TYPE: This 3-bit field indicates the type of the DP. This is signaledaccording to the below table 13.

TABLE 13 Value DP Type 000 DP Type 1 001 DP Type 2 010~111 reserved

DP_GROUP_ID: This 8-bit field identifies the DP group with which thecurrent DP is associated. This can be used by a receiver to access theDPs of the service components associated with a particular service,which will have the same DP_GROUP_ID.

BASE_DP_ID: This 6-bit field indicates the DP carrying service signalingdata (such as PSI/SI) used in the Management layer. The DP indicated byBASE_DP_ID may be either a normal DP carrying the service signaling dataalong with the service data or a dedicated DP carrying only the servicesignaling data

DP_FEC_TYPE: This 2-bit field indicates the FEC type used by theassociated DP. The FEC type is signaled according to the below table 14.

TABLE 14 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10~11 Reserved

DP_COD: This 4-bit field indicates the code rate used by the associatedDP. The code rate is signaled according to the below table 15.

TABLE 15 Value Code rate 0000 5/15 0001 6/15 0010 7/15 0011 8/15 01009/15 0101 10/15  0110 11/15  0111 12/15  1000 13/15  1001~1111 Reserved

DP_MOD: This 4-bit field indicates the modulation used by the associatedDP. The modulation is signaled according to the below table 16.

TABLE 16 Value Modulation 0000 QPSK 0001 QAM-16 0010 NUQ-64 0011 NUQ-2560100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111 NUC-256 1000 NUC-10241001~1111 reserved

DP_SSD_FLAG: This 1-bit field indicates whether the SSD mode is used inthe associated DP. If this field is set to value ‘1’, SSD is used. Ifthis field is set to value ‘0’, SSD is not used.

The following field appears only if PHY_PROFILE is equal to ‘010’, whichindicates the advanced profile:

DP_MIMO: This 3-bit field indicates which type of MIMO encoding processis applied to the associated DP. The type of MIMO encoding process issignaled according to the table 17.

TABLE 17 Value MIMO encoding 000 FR-SM 001 FRFD-SM 010~111 reserved

DP_TI_TYPE: This 1-bit field indicates the type of time-interleaving. Avalue of ‘0’ indicates that one TI group corresponds to one frame andcontains one or more TI-blocks. A value of ‘1’ indicates that one TIgroup is carried in more than one frame and contains only one TI-block.

DP_TI_LENGTH: The use of this 2-bit field (the allowed values are only1, 2, 4, 8) is determined by the values set within the DP_TI_TYPE fieldas follows:

If the DP_TI_TYPE is set to the value ‘1’, this field indicates PI, thenumber of the frames to which each TI group is mapped, and there is oneTI-block per TI group (NTI=1). The allowed PI values with 2-bit fieldare defined in the below table 18.

If the DP_TI_TYPE is set to the value ‘0’, this field indicates thenumber of TI-blocks NTI per TI group, and there is one TI group perframe (PI=1). The allowed PI values with 2-bit field are defined in thebelow table 18.

TABLE 18 2-bit field P_(I) N_(TI) 00 1 1 01 2 2 10 4 3 11 8 4

DP_FRAME_INTERVAL: This 2-bit field indicates the frame interval (IJUMP)within the frame-group for the associated DP and the allowed values are1, 2, 4, 8 (the corresponding 2-bit field is ‘00’, ‘01’, ‘10’, or ‘11’,respectively). For DPs that do not appear every frame of theframe-group, the value of this field is equal to the interval betweensuccessive frames. For example, if a DP appears on the frames 1, 5, 9,13, etc., this field is set to ‘4’. For DPs that appear in every frame,this field is set to ‘1’.

DP_TI_BYPASS: This 1-bit field determines the availability of timeinterleaver 5050. If time interleaving is not used for a DP, it is setto ‘1’. Whereas if time interleaving is used it is set to ‘0’.

DP_FIRST_FRAME_IDX: This 5-bit field indicates the index of the firstframe of the super-frame in which the current DP occurs. The value ofDP_FIRST_FRAME_IDX ranges from 0 to 31

DP_NUM_BLOCK_MAX: This 10-bit field indicates the maximum value ofDP_NUM_BLOCKS for this DP. The value of this field has the same range asDP_NUM_BLOCKS.

DP_PAYLOAD_TYPE: This 2-bit field indicates the type of the payload datacarried by the given DP. DP_PAYLOAD_TYPE is signaled according to thebelow table 19.

TABLE 19 Value Payload Type 00 TS. 01 IP 10 GS 11 reserved

DP_INBAND_MODE: This 2-bit field indicates whether the current DPcarries in-band signaling information. The in-band signaling type issignaled according to the below table 20.

TABLE 20 Value In-band mode 00 In-band signaling is not carried. 01INBAND-PLS is carried only 10 INBAND-ISSY is carried only 11 INBAND-PLSand INBAND-ISSY are carried

DP_PROTOCOL_TYPE: This 2-bit field indicates the protocol type of thepayload carried by the given DP. It is signaled according to the belowtable 21 when input payload types are selected.

TABLE 21 If DP_PAYLOAD_TYPE If DP_PAYLOAD_TYPE If DP_PAYLOAD_TYPE ValueIs TS Is IP Is GS 00 MPEG2-TS IPv4 (Note) 01 Reserved IPv6 Reserved 10Reserved Reserved Reserved 11 Reserved Reserved Reserved

DP_CRC_MODE: This 2-bit field indicates whether CRC encoding is used inthe Input Formatting block. The CRC mode is signaled according to thebelow table 22.

TABLE 22 Value CRC mode 00 Not used 01 CRC-8 10 CRC-16 11 CRC-32

DNP_MODE: This 2-bit field indicates the null-packet deletion mode usedby the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). DNP_MODEis signaled according to the below table 23. If DP_PAYLOAD_TYPE is notTS (‘00’), DNP_MODE is set to the value ‘00’.

TABLE 23 Value Null-packet deletion mode 00 Not used 01 DNP-NORMAL 10DNP-OFFSET 11 reserved

ISSY_MODE: This 2-bit field indicates the ISSY mode used by theassociated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). The ISSY_MODE issignaled according to the below table 24 If DP_PAYLOAD_TYPE is not TS(‘00’), ISSY_MODE is set to the value ‘00’.

TABLE 24 Value ISSY mode 00 Not used 01 ISSY-UP 10 ISSY-BBF 11 reserved

HC_MODE_TS: This 2-bit field indicates the TS header compression modeused by the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). TheHC_MODE_TS is signaled according to the below table 25.

TABLE 25 Value Header compression mode 00 HC_MODE_TS 1 01 HC_MODE_TS 210 HC_MODE_TS 3 11 HC_MODE_TS 4HC_MODE_IP: This 2-bit field indicates the IP header compression modewhen DP_PAYLOAD_TYPE is set to IP (‘01’). The HC_MODE_IP is signaledaccording to the below table 26.

TABLE 26 Value Header compression mode 00 No compression 01 HC_MODE_IP 110~11 reserved

PID: This 13-bit field indicates the PID number for TS headercompression when DP_PAYLOAD_TYPE is set to TS (‘00’) and HC_MODE_TS isset to ‘01’ or ‘10’.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if FIC_FLAG is equal to ‘1’:

FIC_VERSION: This 8-bit field indicates the version number of the FIC.

FIC_LENGTH_BYTE: This 13-bit field indicates the length, in bytes, ofthe FIC.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if AUX_FLAG is equal to ‘1’:

NUM_AUX: This 4-bit field indicates the number of auxiliary streams.Zero means no auxiliary streams are used.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use.

AUX_STREAM_TYPE: This 4-bit is reserved for future use for indicatingthe type of the current auxiliary stream.

AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future use forsignaling auxiliary streams.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 15 illustrates PLS2-DYN data of the PLS2 data. The values of thePLS2-DYN data may change during the duration of one frame-group, whilethe size of fields remains constant.

The details of fields of the PLS2-DYN data are as follows:

FRAME_INDEX: This 5-bit field indicates the frame index of the currentframe within the super-frame. The index of the first frame of thesuper-frame is set to ‘0’.

PLS_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration will change. The nextsuper-frame with changes in the configuration is indicated by the valuesignaled within this field. If this field is set to the value ‘0000’, itmeans that no scheduled change is foreseen: e.g., value ‘1’ indicatesthat there is a change in the next super-frame.

FIC_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration (i.e., the contents of theFIC) will change. The next super-frame with changes in the configurationis indicated by the value signaled within this field. If this field isset to the value ‘0000’, it means that no scheduled change is foreseen:e.g. value ‘0001’ indicates that there is a change in the nextsuper-frame.

RESERVED: This 16-bit field is reserved for future use.

The following fields appear in the loop over NUM_DP, which describe theparameters associated with the DP carried in the current frame.

DP_ID: This 6-bit field indicates uniquely the DP within a PHY profile.

DP_START: This 15-bit (or 13-bit) field indicates the start position ofthe first of the DPs using the DPU addressing scheme. The DP_START fieldhas differing length according to the PHY profile and FFT size as shownin the below table 27.

TABLE 27 DP_START field size PHY profile 64K 16K Base 13 bit 15 bitHandheld — 13 bit Advanced 13 bit 15 bit

DP_NUM_BLOCK: This 10-bit field indicates the number of FEC blocks inthe current TI group for the current DP. The value of DP_NUM_BLOCKranges from 0 to 1023

RESERVED: This 8-bit field is reserved for future use.

The following fields indicate the FIC parameters associated with theEAC.

EAC_FLAG: This 1-bit field indicates the existence of the EAC in thecurrent frame. This bit is the same value as the EAC_FLAG in thepreamble.

EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates the version numberof a wake-up indication.

If the EAC_FLAG field is equal to ‘1’, the following 12 bits areallocated for EAC_LENGTH_BYTE field. If the EAC_FLAG field is equal to‘0’, the following 12 bits are allocated for EAC_COUNTER.

EAC_LENGTH_BYTE: This 12-bit field indicates the length, in byte, of theEAC.

EAC_COUNTER: This 12-bit field indicates the number of the frames beforethe frame where the EAC arrives.

The following field appears only if the AUX_FLAG field is equal to ‘1’:

AUX_PRIVATE_DYN: This 48-bit field is reserved for future use forsignaling auxiliary streams. The meaning of this field depends on thevalue of AUX_STREAM_TYPE in the configurable PLS2-STAT.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS2.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

As above mentioned, the PLS, EAC, FIC, DPs, auxiliary streams and dummycells are mapped into the active carriers of the OFDM symbols in theframe. The PLS1 and PLS2 are first mapped into one or more FSS(s). Afterthat, EAC cells, if any, are mapped immediately following the PLS field,followed next by FIC cells, if any. The DPs are mapped next after thePLS or EAC, FIC, if any. Type 1 DPs follows first, and Type 2 DPs next.The details of a type of the DP will be described later. In some case,DPs may carry some special data for EAS or service signaling data. Theauxiliary stream or streams, if any, follow the DPs, which in turn arefollowed by dummy cells. Mapping them all together in the abovementioned order, i.e. PLS, EAC, FIC, DPs, auxiliary streams and dummydata cells exactly fill the cell capacity in the frame.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

PLS cells are mapped to the active carriers of FSS(s). Depending on thenumber of cells occupied by PLS, one or more symbols are designated asFSS(s), and the number of FSS(s) NFSS is signaled by NUM_FSS in PLS1.The FSS is a special symbol for carrying PLS cells. Since robustness andlatency are critical issues in the PLS, the FSS(s) has higher density ofpilots allowing fast synchronization and frequency-only interpolationwithin the FSS.

PLS cells are mapped to active carriers of the NFSS FSS(s) in a top-downmanner as shown in an example in FIG. 17. The PLS1 cells are mappedfirst from the first cell of the first FSS in an increasing order of thecell index. The PLS2 cells follow immediately after the last cell of thePLS1 and mapping continues downward until the last cell index of thefirst FSS. If the total number of required PLS cells exceeds the numberof active carriers of one FSS, mapping proceeds to the next FSS andcontinues in exactly the same manner as the first FSS.

After PLS mapping is completed, DPs are carried next. If EAC, FIC orboth are present in the current frame, they are placed between PLS and“normal” DPs.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

EAC is a dedicated channel for carrying EAS messages and links to theDPs for EAS. EAS support is provided but EAC itself may or may not bepresent in every frame. EAC, if any, is mapped immediately after thePLS2 cells. EAC is not preceded by any of the FIC, DPs, auxiliarystreams or dummy cells other than the PLS cells. The procedure ofmapping the EAC cells is exactly the same as that of the PLS.

The EAC cells are mapped from the next cell of the PLS2 in increasingorder of the cell index as shown in the example in FIG. 18. Depending onthe EAS message size, EAC cells may occupy a few symbols, as shown inFIG. 18.

EAC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required EAC cells exceeds the number of remainingactive carriers of the last FSS mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol, which has more activecarriers than a FSS.

After EAC mapping is completed, the FIC is carried next, if any exists.If FIC is not transmitted (as signaled in the PLS2 field), DPs followimmediately after the last cell of the EAC.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

shows an example mapping of FIC cell without EAC and (b) shows anexample mapping of FIC cell with EAC.

FIC is a dedicated channel for carrying cross-layer information toenable fast service acquisition and channel scanning. This informationprimarily includes channel binding information between DPs and theservices of each broadcaster. For fast scan, a receiver can decode FICand obtain information such as broadcaster ID, number of services, andBASE_DP_ID. For fast service acquisition, in addition to FIC, base DPcan be decoded using BASE_DP_ID. Other than the content it carries, abase DP is encoded and mapped to a frame in exactly the same way as anormal DP. Therefore, no additional description is required for a baseDP. The FIC data is generated and consumed in the Management Layer. Thecontent of FIC data is as described in the Management Layerspecification.

The FIC data is optional and the use of FIC is signaled by the FIC_FLAGparameter in the static part of the PLS2. If FIC is used, FIC_FLAG isset to ‘1’ and the signaling field for FIC is defined in the static partof PLS2. Signaled in this field are FIC_VERSION, and FIC_LENGTH_BYTE.FIC uses the same modulation, coding and time interleaving parameters asPLS2. FIC shares the same signaling parameters such as PLS2_MOD andPLS2_FEC. FIC data, if any, is mapped immediately after PLS2 or EAC ifany. FIC is not preceded by any normal DPs, auxiliary streams or dummycells. The method of mapping FIC cells is exactly the same as that ofEAC which is again the same as PLS.

Without EAC after PLS, FIC cells are mapped from the next cell of thePLS2 in an increasing order of the cell index as shown in an example in(a). Depending on the FIC data size, FIC cells may be mapped over a fewsymbols, as shown in (b).

FIC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required FIC cells exceeds the number of remainingactive carriers of the last FSS, mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol which has more activecarriers than a FSS.

If EAS messages are transmitted in the current frame, EAC precedes FIC,and FIC cells are mapped from the next cell of the EAC in an increasingorder of the cell index as shown in (b).

After FIC mapping is completed, one or more DPs are mapped, followed byauxiliary streams, if any, and dummy cells.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

shows type 1 DP and (b) shows type 2 DP.

After the preceding channels, i.e., PLS, EAC and FIC, are mapped, cellsof the DPs are mapped. A DP is categorized into one of two typesaccording to mapping method:

Type 1 DP: DP is mapped by TDM

Type 2 DP: DP is mapped by FDM

The type of DP is indicated by DP_TYPE field in the static part of PLS2.FIG. 20 illustrates the mapping orders of Type 1 DPs and Type 2 DPs.Type 1 DPs are first mapped in the increasing order of cell index, andthen after reaching the last cell index, the symbol index is increasedby one. Within the next symbol, the DP continues to be mapped in theincreasing order of cell index starting from p=0. With a number of DPsmapped together in one frame, each of the Type 1 DPs are grouped intime, similar to TDM multiplexing of DPs.

Type 2 DPs are first mapped in the increasing order of symbol index, andthen after reaching the last OFDM symbol of the frame, the cell indexincreases by one and the symbol index rolls back to the first availablesymbol and then increases from that symbol index. After mapping a numberof DPs together in one frame, each of the Type 2 DPs are grouped infrequency together, similar to FDM multiplexing of DPs.

Type 1 DPs and Type 2 DPs can coexist in a frame if needed with onerestriction; Type 1 DPs always precede Type 2 DPs. The total number ofOFDM cells carrying Type 1 and Type 2 DPs cannot exceed the total numberof OFDM cells available for transmission of DPs:D _(DP1) +D _(DP2) ≦D _(DP)  [Math figure 2]

where DDP1 is the number of OFDM cells occupied by Type 1 DPs, DDP2 isthe number of cells occupied by Type 2 DPs. Since PLS, EAC, FIC are allmapped in the same way as Type 1 DP, they all follow “Type 1 mappingrule”. Hence, overall, Type 1 mapping always precedes Type 2 mapping.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

shows an addressing of OFDM cells for mapping type 1 DPs and (b) showsan addressing of OFDM cells for mapping for type 2 DPs.

Addressing of OFDM cells for mapping Type 1 DPs (0, . . . , DDP1-1) isdefined for the active data cells of Type 1 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 1DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Without EAC and FIC, address 0 refers to the cell immediately followingthe last cell carrying PLS in the last FSS. If EAC is transmitted andFIC is not in the corresponding frame, address 0 refers to the cellimmediately following the last cell carrying EAC. If FIC is transmittedin the corresponding frame, address 0 refers to the cell immediatelyfollowing the last cell carrying FIC. Address 0 for Type 1 DPs can becalculated considering two different cases as shown in (a). In theexample in (a), PLS, EAC and FIC are assumed to be all transmitted.Extension to the cases where either or both of EAC and FIC are omittedis straightforward. If there are remaining cells in the FSS aftermapping all the cells up to FIC as shown on the left side of (a).

Addressing of OFDM cells for mapping Type 2 DPs (0, . . . , DDP2-1) isdefined for the active data cells of Type 2 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 2DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Three slightly different cases are possible as shown in (b). For thefirst case shown on the left side of (b), cells in the last FSS areavailable for Type 2 DP mapping. For the second case shown in themiddle, FIC occupies cells of a normal symbol, but the number of FICcells on that symbol is not larger than CFSS. The third case, shown onthe right side in (b), is the same as the second case except that thenumber of FIC cells mapped on that symbol exceeds CFSS.

The extension to the case where Type 1 DP(s) precede Type 2 DP(s) isstraightforward since PLS, EAC and FIC follow the same “Type 1 mappingrule” as the Type 1 DP(s).

A data pipe unit (DPU) is a basic unit for allocating data cells to a DPin a frame.

A DPU is defined as a signaling unit for locating DPs in a frame. A CellMapper 7010 may map the cells produced by the TIs for each of the DPs. ATime interleaver 5050 outputs a series of TI-blocks and each TI-blockcomprises a variable number of XFECBLOCKs which is in turn composed of aset of cells. The number of cells in an XFECBLOCK, Ncells, is dependenton the FECBLOCK size, Nldpc, and the number of transmitted bits perconstellation symbol. A DPU is defined as the greatest common divisor ofall possible values of the number of cells in a XFECBLOCK, Ncells,supported in a given PHY profile. The length of a DPU in cells isdefined as LDPU. Since each PHY profile supports different combinationsof FECBLOCK size and a different number of bits per constellationsymbol, LDPU is defined on a PHY profile basis.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention before bit interleaving. As above mentioned, Data FECencoder may perform the FEC encoding on the input BBF to generateFECBLOCK procedure using outer coding (BCH), and inner coding (LDPC).The illustrated FEC structure corresponds to the FECBLOCK. Also, theFECBLOCK and the FEC structure have same value corresponding to a lengthof LDPC codeword.

The BCH encoding is applied to each BBF (Kbch bits), and then LDPCencoding is applied to BCH-encoded BBF (Kldpc bits=Nbch bits) asillustrated in FIG. 22.

The value of Nldpc is either 64800 bits (long FECBLOCK) or 16200 bits(short FECBLOCK).

The below table 28 and table 29 show FEC encoding parameters for a longFECBLOCK and a short FECBLOCK, respectively.

TABLE 28 BCH error LDPC correction Rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 64800 21600 21408 12 192 6/15 2592025728 7/15 30240 30048 8/15 34560 34368 9/15 38880 38688 10/15  4320043008 11/15  47520 47328 12/15  51840 51648 13/15  56160 55968

TABLE 29 BCH error LDPC correction Rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 16200 5400 5232 12 168 6/15 6480 63127/15 7560 7392 8/15 8640 8472 9/15 9720 9552 10/15  10800 10632 11/15 11880 11712 12/15  12960 12792 13/15  14040 13872

The details of operations of the BCH encoding and LDPC encoding are asfollows:

A 12-error correcting BCH code is used for outer encoding of the BBF.The BCH generator polynomial for short FECBLOCK and long FECBLOCK areobtained by multiplying together all polynomials.

LDPC code is used to encode the output of the outer BCH encoding. Togenerate a completed Bldpc (FECBLOCK), Pldpc (parity bits) is encodedsystematically from each Ildpc (BCH-encoded BBF), and appended to Ildpc.The completed Bldpc (FECBLOCK) are expressed as follow Math figure.B _(ldpc)=[I _(ldpc) P _(ldpc)]=[i ₀ ,i ₁ , . . . ,i _(K) _(ldpc) ⁻¹ ,p₀ ,p ₁ , . . . ,p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹]  [Math figure 3]

The parameters for long FECBLOCK and short FECBLOCK are given in theabove table 28 and 29, respectively.

The detailed procedure to calculate Nldpc−Kldpc parity bits for longFECBLOCK, is as follows:

1) Initialize the parity bits,p ₀ =p ₁ =p ₂ = . . . =p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹=0  [Math figure4]

2) Accumulate the first information bit −i0, at parity bit addressesspecified in the first row of an addresses of parity check matrix. Thedetails of addresses of parity check matrix will be described later. Forexample, for rate 13/15:p ₉₈₃ =p ₉₈₃ ⊕i ₀ p ₂₈₁₅ =p ₂₈₁₅ ⊕i ₀p ₄₈₃₇ =p ₄₈₃₇ ⊕i ₀ p ₄₉₈₉ =p ₄₉₈₉ ⊕i ₀p ₆₁₃₈ =p ₆₁₃₈ ⊕i ₀ p ₆₄₅₈ =p ₆₄₅₈ ⊕i ₀p ₆₉₂₁ =p ₆₉₂₁ ⊕i ₀ p ₆₉₇₄ =p ₆₉₇₄ ⊕i ₀p ₇₅₇₂ =p ₇₅₇₂ ⊕i ₀ p ₈₂₆₀ =p ₈₂₆₀ ⊕i ₀p ₈₄₉₆ =p ₈₄₉₆ ⊕i ₀  [Math figure 5]

3) For the next 359 information bits, is, s=1, 2, . . . , 359 accumulateis at parity bit addresses using following Math figure.{x+(s mod 360)×Q _(ldpc)} mod(N _(ldpc) −K _(lpdc))  [Math figure 6]

where x denotes the address of the parity bit accumulator correspondingto the first bit i0, and Qldpc is a code rate dependent constantspecified in the addresses of parity check matrix. Continuing with theexample, Qldpc=24 for rate 13/15, so for information bit i1, thefollowing operations are performed:p ₁₀₀₇ =p ₁₀₀₇ ⊕i ₁ p ₂₈₃₉ =p ₂₈₃₉ ⊕i ₁p ₄₈₆₁ =p ₄₈₆₁ ⊕i ₁ p ₅₀₁₃ =p ₅₀₁₃ ⊕i ₁p ₆₁₆₂ =p ₆₁₆₂ ⊕i ₁ p ₆₄₈₂ =p ₆₄₈₂ ⊕i ₁p ₆₉₄₅ =p ₆₉₄₅ ⊕i ₁ p ₆₉₉₈ =p ₆₉₉₈ ⊕i ₁p ₇₅₉₆ =p ₇₅₉₆ ⊕i ₁ p ₈₂₈₄ =p ₈₂₈₄ ⊕i ₁p ₈₅₂₀ =p ₈₅₂₀ ⊕i ₁  [Math figure 7]

4) For the 361st information bit i360, the addresses of the parity bitaccumulators are given in the second row of the addresses of paritycheck matrix. In a similar manner the addresses of the parity bitaccumulators for the following 359 information bits is, s=361, 362, . .. , 719 are obtained using the Math FIG. 6, where x denotes the addressof the parity bit accumulator corresponding to the information bit i360,i.e., the entries in the second row of the addresses of parity checkmatrix.

5) In a similar manner, for every group of 360 new information bits, anew row from addresses of parity check matrixes used to find theaddresses of the parity bit accumulators.

After all of the information bits are exhausted, the final parity bitsare obtained as follows:

6) Sequentially perform the following operations starting with i=1p _(i) =p _(i) ⊕p _(i-1) , i=1,2, . . . ,N _(ldpc) −K _(ldpc)−1  [Mathfigure 8]

where final content of pi, i=0,1, . . . Nldpc−Kldpc−1 is equal to theparity bit pi.

TABLE 30 Code Rate Q_(ldpc) 5/15 120 6/15 108 7/15 96 8/15 84 9/15 7210/15  60 11/15  48 12/15  36 13/15  24

This LDPC encoding procedure for a short FECBLOCK is in accordance witht LDPC encoding procedure for the long FECBLOCK, except replacing thetable 30 with table 31, and replacing the addresses of parity checkmatrix for the long FECBLOCK with the addresses of parity check matrixfor the short FECBLOCK.

TABLE 31 Code Rate Q_(ldpc) 5/15 30 6/15 27 7/15 24 8/15 21 9/15 1810/15  15 11/15  12 12/15  9 13/15  6

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

The outputs of the LDPC encoder are bit-interleaved, which consists ofparity interleaving followed by Quasi-Cyclic Block (QCB) interleavingand inner-group interleaving.

shows Quasi-Cyclic Block (QCB) interleaving and (b) shows inner-groupinterleaving.

The FECBLOCK may be parity interleaved. At the output of the parityinterleaving, the LDPC codeword consists of 180 adjacent QC blocks in along FECBLOCK and 45 adjacent QC blocks in a short FECBLOCK. Each QCblock in either a long or short FECBLOCK consists of 360 bits. Theparity interleaved LDPC codeword is interleaved by QCB interleaving. Theunit of QCB interleaving is a QC block. The QC blocks at the output ofparity interleaving are permutated by QCB interleaving as illustrated inFIG. 23, where Ncells=64800/η mod or 16200/η mod according to theFECBLOCK length. The QCB interleaving pattern is unique to eachcombination of modulation type and LDPC code rate.

After QCB interleaving, inner-group interleaving is performed accordingto modulation type and order (η mod) which is defined in the below table32. The number of QC blocks for one inner-group, NQCB_IG, is alsodefined.

TABLE 32 Modulation type η_(mod) N_(QCB) _(—) _(IG) QAM-16 4 2 NUC-16 44 NUQ-64 6 3 NUC-64 6 6 NUQ-256 8 4 NUC-256 8 8 NUQ-1024 10 5 NUC-102410 10

The inner-group interleaving process is performed with NQCB_IG QC blocksof the QCB interleaving output. Inner-group interleaving has a processof writing and reading the bits of the inner-group using 360 columns andNQCB_IG rows. In the write operation, the bits from the QCB interleavingoutput are written row-wise. The read operation is performed column-wiseto read out m bits from each row, where m is equal to 1 for NUC and 2for NUQ.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

FIG. 24 shows a cell-word demultiplexing for 8 and 12 bpcu MIMO and (b)shows a cell-word demultiplexing for 10 bpcu MIMO.

Each cell word (c0,1, c1,1, . . . , cη mod−1,1) of the bit interleavingoutput is demultiplexed into (d1,0,m, d1,1,m . . . , d1,η mod−1,m) and(d2,0,m, d2,1,m . . . , d2,η mod−1,m) as shown in (a), which describesthe cell-word demultiplexing process for one XFECBLOCK.

For the 10 bpcu MIMO case using different types of NUQ for MIMOencoding, the Bit Interleaver for NUQ-1024 is re-used. Each cell word(c0,1, c1,1, . . . , c9,1) of the Bit Interleaver output isdemultiplexed into (d1,0,m, d1,1,m . . . , d1,3,m) and (d2,0,m, d2,1,m .. . , d2,5,m), as shown in (b).

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

to (c) show examples of TI mode.

The time interleaver operates at the DP level. The parameters of timeinterleaving (TI) may be set differently for each DP.

The following parameters, which appear in part of the PLS2-STAT data,configure the TI:

DP_TI_TYPE (allowed values: 0 or 1): Represents the TI mode; ‘0’indicates the mode with multiple TI blocks (more than one TI block) perTI group. In this case, one TI group is directly mapped to one frame (nointer-frame interleaving). ‘1’ indicates the mode with only one TI blockper TI group. In this case, the TI block may be spread over more thanone frame (inter-frame interleaving).

DP_TI_LENGTH: If DP_TI_TYPE=‘0’, this parameter is the number of TIblocks NTI per TI group. For DP_TI_TYPE=‘1’, this parameter is thenumber of frames PI spread from one TI group.

DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): Represents the maximumnumber of XFECBLOCKs per TI group.

DP_FRAME_INTERVAL (allowed values: 1, 2, 4, 8): Represents the number ofthe frames IJUMP between two successive frames carrying the same DP of agiven PHY profile.

DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving is not usedfor a DP, this parameter is set to ‘1’. It is set to ‘0’ if timeinterleaving is used.

Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN data is usedto represent the number of XFECBLOCKs carried by one TI group of the DP.

When time interleaving is not used for a DP, the following TI group,time interleaving operation, and TI mode are not considered. However,the Delay Compensation block for the dynamic configuration informationfrom the scheduler will still be required. In each DP, the XFECBLOCKsreceived from the SSD/MIMO encoding are grouped into TI groups. That is,each TI group is a set of an integer number of XFECBLOCKs and willcontain a dynamically variable number of XFECBLOCKs. The number ofXFECBLOCKs in the TI group of index n is denoted by NxBLOCK_Group(n) andis signaled as DP_NUM_BLOCK in the PLS2-DYN data. Note thatNxBLOCK_Group(n) may vary from the minimum value of 0 to the maximumvalue NxBLOCK_Group_MAX (corresponding to DP_NUM_BLOCK_MAX) of which thelargest value is 1023.

Each TI group is either mapped directly onto one frame or spread over PIframes. Each TI group is also divided into more than one TI blocks(NTI), where each TI block corresponds to one usage of time interleavermemory. The TI blocks within the TI group may contain slightly differentnumbers of XFECBLOCKs. If the TI group is divided into multiple TIblocks, it is directly mapped to only one frame. There are three optionsfor time interleaving (except the extra option of skipping the timeinterleaving) as shown in the below table 33.

TABLE 33 Modes Descriptions Option-1 Each TI group contains one TI blockand is mapped directly to one frame as shown in (a). This option issignaled in the PLS2-STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH =‘1’(N_(TI) = 1). Option-2 Each TI group contains one TI block and ismapped to more than one frame. (b) shows an example, where one TI groupis mapped to two frames, i.e., DP_TI_LENGTH = ‘2’ (P_(I) = 2) andDP_FRAME_INTERVAL (I_(JUMP) = 2). This provides greater time diversityfor low data-rate services. This option is signaled in the PLS2- STAT byDP_TI_TYPE = ‘1’. Option-3 Each TI group is divided into multiple TIblocks and is mapped directly to one frame as shown in (c). Each TIblock may use full TI memory, so as to provide the maximum bit-rate fora DP. This option is signaled in the PLS2-STAT signaling by DP_TI_TYPE =‘0’ and DP_TI_LENGTH = N_(TI), while P_(I) = 1.

In each DP, the TI memory stores the input XFECBLOCKs (output XFECBLOCKsfrom the SSD/MIMO encoding block). Assume that input XFECBLOCKs aredefined as

(d_(n, s, 0, 0), d_(n, s, 0, 1), …  , d_(n, s, 0, N_(cells) − 1), d_(n, s, 1, 0), …  , d_(n, s, 1, N_(cells) − 1),   …  , d_(n, s, N_(xBLOCK_TI)(n, s) − 1, 0), …  , d_(n, s, N_(xBLOCK_TI)(n, s) − 1, N_(cells) − 1)),

where d_(n,s,r,q) is the qth cell of the rth XFECBLOCK in the sth TIblock of the nth TI group and represents the outputs of SSD and MIMOencodings as follows

$d_{n,s,r,q} = \left\{ {\begin{matrix}{f_{n,s,r,q},{{theoutputof}\mspace{14mu}{SSD}\mspace{14mu}\ldots\mspace{14mu}{encoding}}} \\{g_{n,s,r,q},{{theoutputof}\mspace{14mu}{MIMO}\mspace{14mu}{encoding}}}\end{matrix}.} \right.$

In addition, assume that output XFECBLOCKs from the time interleaver5050 are defined as

(h_(n, s, 0), h_(n, s, 1), …  , h_(n, s, i), …  , h_(n, s, N_(xBLOCK_TI)(n, s) × N_(cells) − 1)),

where h_(n,s,i) is the ith output cell (for i=0, . . . , N_(xBLOCK) _(_)_(TI)(n,s)×N_(cells)−1) in the sth TI block of the nth TI group.

Typically, the time interleaver will also act as a buffer for DP dataprior to the process of frame building. This is achieved by means of twomemory banks for each DP. The first TI-block is written to the firstbank. The second TI-block is written to the second bank while the firstbank is being read from and so on.

The TI is a twisted row-column block interleaver. For the sth TI blockof the nth TI group, the number of rows N_(r) of a TI memory is equal tothe number of cells N_(cells), i.e., N_(r)=N_(cells), while the numberof columns N_(c) is equal to the number N_(xBLOCK) _(_) _(TI)(n,s).

FIG. 26 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 26 (a) shows a writing operation in the time interleaver and FIG.26(b) shows a reading operation in the time interleaver The firstXFECBLOCK is written column-wise into the first column of the TI memory,and the second XFECBLOCK is written into the next column, and so on asshown in (a). Then, in the interleaving array, cells are read outdiagonal-wise. During diagonal-wise reading from the first row(rightwards along the row beginning with the left-most column) to thelast row, N_(r) cells are read out as shown in (b). In detail, assumingz_(n,s,i) (i=0, . . . , N_(r)N_(c)) as the TI memory cell position to beread sequentially, the reading process in such an interleaving array isperformed by calculating the row index R_(n,s,i), the column indexC_(n,s,i), and the associated twisting parameter T_(n,s,i) as followsexpression.

$\begin{matrix}{{{GENERATE}\left( {R_{n,s,i},C_{n,s,i}} \right)} = \left\{ {{R_{n,s,i} = {{mod}\left( {i,N_{r}} \right)}},{T_{n,s,i} = {{mod}\left( {{S_{shift} \times R_{n,s,i}}, N_{c}} \right)}},{C_{n,s,i} = {{mod}\left( {{T_{n,s,i} + \left\lfloor \frac{i}{N_{r}} \right\rfloor},N_{c}} \right)}}} \right\}} & \left\lbrack {{Math}\mspace{14mu}{Figure}\mspace{14mu} 9} \right\rbrack\end{matrix}$

where S_(shift) is a common shift value for the diagonal-wise readingprocess regardless of N_(xBLOCK) _(_) _(TI)(n,s), and it is determinedby N_(xBLOCK) _(_) _(TI) _(_) _(MAX) given in the PLS2-STAT as followsexpression.

$\begin{matrix}{{for}\left\{ {\begin{matrix}{{N_{{{xBLOCK}\_{TI}}{\_{MAX}}}^{\prime} = {N_{{{xBLOCK}\_{TI}}{\_{MAX}}} + 1}},} \\{{{if}\mspace{14mu} N_{{{xBLOCK}\_{TI}}{\_{MAX}}}{mod2}} = 0} \\{{N_{{{xBLOCK}\_{TI}}{\_{MAX}}}^{\prime} = N_{{{xBLOCK}\_{TI}}{\_{MAX}}}},} \\{{{if}\mspace{14mu} N_{{{xBLOCK}\_{TI}}{\_{MAX}}}{mod2}} = 1^{\prime}}\end{matrix},{S_{shift} = \frac{N_{{{xBLOCK}\_{TI}}{\_{MAX}}}^{\prime} - 1}{2}}} \right.} & \left\lbrack {{Math}\mspace{14mu}{Figure}\mspace{14mu} 10} \right\rbrack\end{matrix}$

As a result, the cell positions to be read are calculated by acoordinate as z_(n,s,i)=N_(r)C_(n,s,i)+R_(n,s,i).

FIG. 27 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

More specifically, FIG. 27 illustrates the interleaving array in the TImemory for each TI group, including virtual XFECBLOCKs when N_(xBLOCK)_(_) _(TI)(0,0)=3, N_(xBLOCK) _(_) _(TI)(1,0)=6, N_(xBLOCK) _(_)_(TI)(2,0)=5.

The variable number N_(xBLOCK) _(_) _(TI)(n,s)=N_(r) will be less thanor equal to N′_(xBLOCK) _(_) _(TI) _(_) _(MAX). Thus, in order toachieve a single-memory deinterleaving at the receiver side, regardlessof N_(xBLOCK) _(_) _(TI)(n,s), the interleaving array for use in atwisted row-column block interleaver is set to the size ofN_(r)×N_(c)=N_(cells)×N′_(xBLOCK) _(_) _(TI) _(_) _(MAX) by insertingthe virtual XFECBLOCKs into the TI memory and the reading process isaccomplished as follow expression.

$\begin{matrix}{{{p = 0};}{{{{for}{\mspace{11mu}\;}i} = 0};{i < {N_{cells}N_{{{xBLOCK}\_{TI}}{\_{MAX}}}^{\prime}}};{i = {i + 1}}}\left\{ {{{GENERATE}\left( {R_{n,s,i}, C_{n,s,i}} \right)};{V_{i} = {{{N_{r}C_{n,s,j}} + {R_{n,s,j}{if}\mspace{14mu} V_{i}}} < {N_{cells}{N_{{xBLOCK}\_{TI}}\left( {n, s} \right)}\left\{ {{Z_{n,s,p} = V_{i}};{p = {p + 1}};} \right\}}}}} \right\}} & \left\lbrack {{Math}\mspace{14mu}{Figure}\mspace{14mu} 11} \right\rbrack\end{matrix}$

The number of TI groups is set to 3. The option of time interleaver issignaled in the PLS2-STAT data by DP_TI_TYPE=‘0’, DP_FRAME_INTERVAL=‘1’,and DP_TI_LENGTH=‘1’, i.e., NTI=1, IJUMP=1, and PI=1. The number ofXFECBLOCKs, each of which has Ncells=30 cells, per TI group is signaledin the PLS2-DYN data by NxBLOCK_TI(0,0)=3, NxBLOCK_TI(1,0)=6, andNxBLOCK_TI(2,0)=5, respectively. The maximum number of XFECBLOCK issignaled in the PLS2-STAT data by NxBLOCK_Group_MAX, which leads to└N_(xBLOCK) _(_) _(Group) _(_) _(MAX)/N_(TI) ┘=N_(xBLOCK) _(_) _(TI)_(_) _(MAX)=6.

FIG. 28 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

More specifically FIG. 28 shows a diagonal-wise reading pattern fromeach interleaving array with parameters of N′_(xBLOCK) _(_) _(TI) _(_)_(MAX)=7 and Sshift=(7−1)/2=3. Note that in the reading process shown aspseudocode above, if V_(i)≧N_(cells)N_(xBLOCK) _(_) _(TI)(n,s), thevalue of Vi is skipped and the next calculated value of Vi is used.

FIG. 29 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 29 illustrates the interleaved XFECBLOCKs from each interleavingarray with parameters of N′_(xBLOCK) _(_) _(TI) _(_) _(MAX)=7 andSshift=3.

Hereinafter, a method of protecting PLS data by the apparatus fortransmitting broadcast signals according to the present embodiment willbe described. As described with reference to FIG. 2, the PLS data mayinclude PLS1 data and PLS2 data.

PLS1 data provides basic transmission parameters including parametersrequired to enable the reception and decoding of PLS2. PLS1 fieldsremain unchanged for /′ the entire duration of one frame-group.

PLS2 contains parameters that provide sufficient information for thereceiver to decode the desired DP. PLS2 signaling further consists oftwo types of parameters, PLS2-STAT and PLS2-DYN. The PLS2-STATparameters are the same within a frame-group, while the PLS2-DYNparameters provide information that is specific to the current frame.The values of the PLS2-DYN parameters may change during the duration ofone frame-group, while the size of fields remains constant.

PLS1 and the static part of PLS2 can be changed only on the border oftwo super-frames. In in-band signaling, there is a counter indicatingthe next super-frame with changes in PLS1 or the static part of the PLS2parameters. The receiver can locate the change boundary by checking thenew PLS parameters from the FSS(s) in the first frame of the announcedsuper-frame, where the indicated change applies.

FIG. 30 illustrates a PLS data protection operation according to anembodiment of the present invention.

FIG. 30(a) illustrates an operation of processing PLS data by theapparatus for transmitting broadcast signals according to the presentembodiment.

FIG. 30(b) illustrates a detailed operation of a shortened/punctured FECencoder (LDPC/BCH) according to the present embodiment.

As illustrated in FIG. 30(a), the PLS data protection operationaccording to the present embodiment may include a physical layersignaling generation block, a PLS scrambler, the shortened/punctured FECencoder (LDPC/BCH), a bit interleaver and a constellation mapper. In thepresent invention, the physical layer signaling generation block may bereferred to as a signaling generation block. Hereinafter, operations ofthe respective functional blocks will be described.

The signaling generation block creates physical layer signalinginformation used for the operation of each functional block. Thissignaling information is also transmitted so that services of interestare properly recovered at the receiver side.

The signaling generation block may generate and output each of the PLS1data and the PLS2 data based on input management information.Thereafter, each of the PLS1 data and the PLS2 data may be independentlyprocessed.

In addition, the signaling generation block may divide and output thePLS data in units for LDPC encoding. In this case, the PLS data dividedin units for LDPC encoding may be referred to as Ksig. In addition, eachof the divided PLS data input to the LDPC encoder may be referred to asan information block or information bits. The signaling generation blockmay not divide the PLS1 data.

Hereinafter, the operation of each functional block may be performed oneach of the PLS1 data and the PLS2 data. In description with referenceto figures below, the PLS data may include the PLS1 data or the PLS2data.

Thereafter, the PLS scrambler may scramble and output input PLS data.The PLS data is scrambled (randomized) for energy dispersal. A detailedoperation of the PLS scrambler will be described below.

Thereafter, the shortened/punctured FEC encoder (LDPC/BCH) may encodethe input scrambled PLS data. The shortened/punctured FEC encoder(LDPC/BCH) may include a BCH encoder with zeros insertion block, an LDPCencoding block, a parity interleaving block and a parity puncturinginserted-zeros removal block. Detailed operations of the respectivefunctional blocks included in the shortened/punctured FEC encoder willbe described with reference to FIG. 30(b).

The shortened/punctured FEC encoder may output shortened and puncturedLDPC-encoded PLS data. The LDPC-encoded PLS data output from theshortened/punctured FEC encoder may be input to the bit interleaver. Thebit interleaver may interleave input bits of the shortened and puncturedLDPC-encoded PLS data.

The bit interleaver according to the present embodiment may adjustreliability of the LDPC-encoded PLS data and of bits in a QAM symbol.The QAM symbol may correspond to a column used in a detailed operationof the bit interleaver to be described below.

Thereafter, the constellation mapper may map the interleaved PLS dataonto the QAM symbol. In this instance, QAM may have a form such as BPSK,QPSK, 16-QAM, 256-QAM, or the like.

As illustrated in FIG. 30(b), the shortened/punctured FEC encoder(LDPC/BCH) according to the present embodiment may include the 90 bit,the LDPC encoding block, the parity interleaving block and the paritypuncturing inserted-zeros removal block. Hereinafter, the operations ofthe respective functional blocks will be described in detail.

The BCH encoder with zeros insertion block may BCH-encode input PLSdata. After the BCH encoding, zero bits are inserted prior to the bitBCH output to generate LDPC encoding input. The LDPC encoding inputaccording to the present embodiment may have a constant length due tothe zero bits inserted in the BCH encoder with zeros insertion block.

In this case, the zero bits inserted into the PLS data may have a sizedetermined based on Table 4. The size of the zero bits inserted into thePLS data may be set to (K_(bch)−K_(sig)). K_(sig) of the PLS2 data maybe a variable unlike K_(sig) of the PLS1 data. Therefore, zero bitsinserted into the PLS2 data may have a size changed depending on K_(sig)and K_(bch).

The apparatus for transmitting broadcast signals according to thepresent embodiment may perform zero bits insertion without BCH encoding.Or the apparatus for transmitting broadcast signals according to thepresent embodiment may not perform both BCH encoding and zero bitsinsertion.

The LDPC encoding block may permute the PLS1 data, which is input fromthe BCH encoder. In this case, the permutation may be performed based ona shortening order or a permutation pattern. The permutation may beperformed in units of 90 bits.

When the apparatus for transmitting broadcast signals according to thepresent embodiment may not perform BCH encoding, LDPC encoding block mayperform permuation to zero inserted PLS data without BCH encoding. Orwhen the apparatus for transmitting broadcast signals according to thepresent embodiment may not perform both BCH encoding and zero bitsinsertion. LDPC encoding block may perform permuation to PLS data only.

The LDPC encoding block may perform column permutation of an H matrix onthe PLS2 data, which is input from the BCH encoder, after LDPC encodingto ensure shortening performance. The apparatus for transmittingbroadcast signals and the apparatus for receiving broadcast signalsaccording to the present embodiment may reduce complexity when encodingand decoding permutated PLS data. The H matrix may be referred to as aparity check matrix.

The LDPC encoding block may perform LDPC encoding on the permuted PLS1data. In addition, the LDPC encoding block may perform LDPC encoding onthe PLS2 data. The LDPC encoding block may output the LDPC-encoded PLSdata in the form of an H matrix. The H matrix output from the LDPCencoding block has a sequential form. In addition, a parity part may berapidly decoded in a dual diagonal (or bit-wise dual diagonal) form bythe apparatus for receiving broadcast signals.

The LDPC encoding block according to the present embodiment may use4K-1/4 LDPC code for the PLS1 data and use 4K-1/4 or 7K-3/10 LDPC codefor PLS2 data to output the H matrix.

The parity interleaving block interleaves parity bits of the LDPC codewhich is the output of the aforementioned LDPC encoding block. Theparity interleaving block may interleave bits of the LDPC code to outputthe bits in a form of a quasi-cyclic block (QCB) (block-wise dualdiagonal form). The LDPC code output in the form of the QCB may beaddressed in QC units by a receiver.

Thereafter, the parity puncturing inserted-zeros removal block maypuncture a portion of LDPC parity bits in LDPC encoded bits of PLS data,and remove zero bits which are inserted after BCH encoding to outputencoded PLS data. The parity puncturing inserted-zeros removal blockaccording to the present embodiment may output encoded PLS data having aparticular code rate by adjusting the punctured parity bits and theremoved zero bits.

The punctured parity bits may have a size determined based on thefollowing expression.

$\quad\left\{ \begin{matrix}{{{{floor}\left( {1.38 \times \left( {{Kbch} - {Ksig}} \right)} \right)} + 1346},{{{if}\mspace{14mu}{Ksig}} < 1021}} \\{{{{floor}\left( {1.41 \times \left( {{Kbch} - {Ksig}} \right)} \right)} + 1620},{otherwise}}\end{matrix} \right.$

Here, Ksig denotes a size of the scrambled PLS data output by the PLSscrambler, and Kbch is set to 1020 or 2100 depending on the size of Ksig(see Table 4).

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 31 illustrates the PLS scrambler according to the presentembodiment.

The PLS scrambler illustrated in FIG. 31 may be a linear shift feedbackregister (LSFR).

All Ksig blocks of PLS1 and PLS2 blocks are scrambled before BCHencoding and shortened and punctured LDPC encoding. The generatorpolynomial of the randomizer is the same as that of the BBF. Thefeed-back shift register is loaded with the initial sequence (0xC089) atthe start of every PLS1 information block and every segmented PLS2information block.

FIG. 32 illustrates a detailed operation of the parity interleavingblock using a PLS data structure.

FIG. 32(a) illustrates a structure of the LDPC-encoded PLS data outputby the LDPC encoding block.

FIG. 32(b) illustrates a detailed operation of the shortened/puncturedFEC encoder (LDPC/BCH) according to the present embodiment. Operationsof respective functional blocks of FIG. 32(b) are identical to theoperations of the respective functional blocks described with referenceto FIG. 30(b).

FIG. 32(c) illustrates a structure of the LDPC-encoded PLS datasubjected to parity interleaving and output by the parity interleavingblock.

The LDPC-encoded PLS data illustrated in FIG. 32(a) is output from theLDPC encoding block. The LDPC-encoded PLS data may include LDPC info(Kldpc) and LDPC parity (Nldpc−Kldpc). LDPC info (Kldpc) may include BCHinfo and BCH parity. BCH info may include encoded PLS data and zeroinserted bits. LDPC parity (Nldpc−Kldpc) may include Qldpc paritygroups. Qldpc has a size determined based on a size of the PLS datawhich is divided in units for LDPC encoding and input to the LDPCencoder (see Table 4). As illustrated in FIG. 32(a), each of parityblocks having a length of Qldpc may include a parity bit of 1^(st)parity group, a parity bit of 2^(nd) parity group, . . . , and a bit of90^(th) parity group.

Parity interleaved PLS data illustrated in FIG. 32(c) is output from theparity interleaving block. The parity interleaved PLS data may includeLDPC info (Kldpc) and LDPC parity (Nldpc−Kldpc). The parity interleavingblock may collect parity bits of LDPC parity (Nldpc−Kldpc) for eachparity group. In this case, each parity group may be 90-QCB.

The apparatus for transmitting broadcast signals according to thepresent embodiment may not perform BCH encoding as above described inFIG. 30. In this case, LDPC info.(Kldpc) represented in FIG. 32(a) andFIG. 32(c) may not include BCH parity. Or LDPC info.(Kldpc) may notinclude BCH parity and zero bits. That is, LDPC info.(Kldpc) may includePLS data and zero inserted bits or may include only PLS data.

FIG. 33 illustrates an operation of a bit-interleaving block of theapparatus for transmitting broadcast signals according to the presentembodiment.

The operation of the bit-interleaving block may be performed in twotypes according to a modulation order. Hereinafter, operations of thebit-interleaving block will be described for a case in which themodulation order is BPSK and a case in which the modulation order isQPSK, higher order QAM, or QAM order.

FIG. 33(a) illustrates a bit interleaving operation for BPSK accordingto an embodiment of the present invention.

In the case of BPSK, there are two branches for bit interleaving toduplicate FEC coded bits in the real and imaginary parts. In this case,the bit-interleaving block may obtain diversity gain by distributingbits to real and imaginary parts. Each coded block is written to theupper branch first. The bits are mapped to the lower branch by applyingmodulo N_(FEC)/2 addition with cyclic shifting value floor (N_(FEC)/2),where N_(FEC) is the length of each LDPC coded block after shorteningand puncturing. Consequently, the input of the cell-word constellationmapping is defined as:[c _(0i) ,c _(1i)]=[b _(i) ,t _(i)], t _(i) =b _((i+floor(N) _(FEC)_(/2))mod N) _(FEC) , i=0,1, . . . ,N _(FEC)−1.

FIG. 33(b) illustrates that the bit-interleaving block of the apparatusfor transmitting broadcast signals according to the present embodimentperforms block interleaving based on QPSK, higher order QAM, and QAMorder.

FIG. 33(b) schematically illustrates a writing operation in a) Writeprocess. In other modulation cases, such as QSPK, QAM-16 and NUQ-64, FECcoded bits are written serially into the interleaver column-wise, wherethe number of columns is the same as the modulation order. That is,QPSK, 16-QAM, QAM-64(NUQ-64) and QAM-256(NUQ-256) have the columnnumbers of 2, 4, 6 and 8, respectively.

FIG. 33(b) schematically illustrates a read operation in b) Readprocess. In the read operation, the bits for one constellation symbolare read out sequentially row-wise and fed into the bit demultiplexerblock (see b) Read process of FIG. 33(b)). These operations arecontinued until the end of the column.

The bit-interleaving block according to the present embodiment may mapLDPC info bits and parity bits onto one symbol as equally as possible,which is intended to avoid a situation in which the LDPC info bits arenulled simultaneously with some of symbols included in a broadcastsignal when the some symbols are nulled. In this way, the apparatus forreceiving broadcast signals according to the present embodiment, whichreceives the broadcast signal, may enhance performance on a fadingchannel while maintaining performance on an additive white Gaussiannoise (AWGN) channel.

FIG. 34 illustrates a detailed operation of a bit demultiplexer (demux)of the apparatus for transmitting broadcast signals according to thepresent embodiment.

FIG. 34(a) shows the bit demultiplexing rule for QAM-16, QAM-64 andQAM-256. This operation continues until all bit groups are read from thebit-interleaving block. Specifically, a) bit-interleaving outputillustrates a structure of data output by the bit-interleaving block,and b) constellation mapper output illustrates a structure of dataoutput by the constellation mapper.

FIG. 34(b) shows equations for a higher QAM bit demuxing rule.

Hereinafter, the higher QAM bit demuxing rule shown in FIG. 34(b) willbe described in detail.

Sdemux_in(i) is a bit demux input. That is, Sdemux_in(i) is an output ofa block interleaver. A value i corresponds to a column index of theblock interleaver. Sdemux_out(i) is an output of the bit demux.

η_(MOD) denotes a modulation order. That is, 16-QAM has a modulationorder of 4, 64-QAM(NUQ-64) has a modulation order of 6, and256-QAM(NuQ-256) has a modulation order of 8. When the bit demuxaccording to the present embodiment performs demultiplexing based on therule shown in FIG. 34(b), information bits of LDPC may be uniformlydistributed from an MSB to an LSB of the QAM symbol.

The bit demux may enhance reliability of the broadcast signal byperforming demultiplexing on bit-interleaved PLS data.

Each bit-interleaved group is demultiplexed bit-by-bit in a group beforeconstellation mapping. Depending on modulation order, there are twomapping rules. In the case of BPSK and QPSK, the reliability of bits ina symbol is equal. Therefore, the bit group read out from thebit-interleaving block is mapped to a QAM symbol without any operation.In the case of QAM-n (n is 16 or more) (also including non-uniform QAMand non-uniform constellation), bits in the QAM symbol may havedifferent reliabilities. In addition, an information bit of the PLSdata, which is bit-interleaved based on the number ofshortened/punctured bits, may be positioned in the MSB first.

The bit demux may perform bit demultiplexing on the bit-interleaved PLSdata to enhance reliability of the bit-interleaved PLS data. However,when the bit demux is separately configured based on the variable numberof shortened/punctured bits, complexity may be induced. The bit demuxaccording to the present embodiment may circular-shift the PLS databased on the QAM order and map the circular-shifted PLS data onto theQAM symbol. The bit demux according to the present embodiment mayperform mapping such that LDPC-encoded bits are uniformly distributed inthe QAM symbol.

FIG. 35 illustrates a result obtained by mapping bits input to theconstellation mapper onto the QAM symbol and outputting the mapped bitsby the constellation mapper according to the present embodiment.

QSPK is mapped as described in FIG. 35 (a).

NUQ 64 is mapped as described in FIG. 35 (b).

QAM-16 is mapped as described in FIG. 35 (c).

Hereinafter, a detailed operation of the constellation mapper will bedescribed.

The constellation mapper according to the present embodiment may map PLSdata subjected to both bit interleaving and bit demultiplexing, or PLSdata subjected only to bit interleaving onto the QAM symbol. Theconstellation mapper according to the present embodiment may change asymbol mapping scheme based on a targeted SNR. As described in theforegoing, the present invention may define three physical layer (PL)profiles: base, handheld and advanced profiles, each optimized tominimize receiver complexity while attaining the performance required ina particular use case. The constellation mapper according to the presentembodiment may map PLS data of a profile (which may be a base profile oran advanced profile) for a mobile environment in a BPSK (or QPSK)scheme. In addition, the constellation mapper according to the presentembodiment may map PLS data of a profile (which may be a handheldprofile) for a fixed reception environment according to a 16-QAM orNUQ-64 scheme. When the constellation mapper according to the presentembodiment maps the PLS data in an NUQ scheme, enhanced shaping gain androbustness may be acquired without increase in complexity compared to acase in which PLS data is mapped in a uniform QAM scheme. On the otherhand, when the constellation mapper according to the present embodimentmaps the PLS data according to the 16-QAM scheme, a gain difference issmall compared to a case in which the PLS data is mapped in the NUQscheme. Therefore, the constellation mapper according to the presentembodiment may map the PLS data in the NUQ scheme without using the QAMscheme for a higher order than 16-QAM.

A code rate applied to the NUQ-64 scheme according to the presentembodiment may be in a range of 5/15, 6/15, . . . , 13/15. Therefore,the constellation mapper according to the present embodiment may use the5/15 code rate when mapping the PLS data using the NUQ-64 scheme. Sincea code rate value that may be applied at the time of encoding the PLSdata is 1/4 or 3/10, the constellation mapper according to the presentembodiment may use 5/15 which is a code rate closest to 1/4 or 3/10.

FIG. 36 illustrates that PLS data decoding is performed in the apparatusfor receiving broadcast signals according to the present embodiment.

Each of functional blocks of the apparatus for receiving broadcastsignals shown in FIG. 36 may perform a reverse procedure of the PLS dataprotection procedure of the apparatus for transmitting broadcast signalsdescribed with reference to FIGS. 30 to 35. However, paritydeinterleaving corresponding to a reverse procedure of the parityinterleaving may not be performed.

Blocks that perform the PLS data decoding according to the presentembodiment may include a constellation demapper, a bit de-interleaver, ashortened/punctured FEC decoder (LDPC/BCH), a PLS descrambler and aphysical layer signaling decoder. The blocks that perform the PLS datadecoding shown in FIG. 36 may perform the operation of the signalingdecoding block 9040 described above with reference to FIG. 9. When theapparatus for receiving broadcast signals according to the presentembodiment receives PLS data that is unprocessed BCH encoding operation,the PLS data decoding operation according to the present embodiment maybe omitted.

The shortened/punctured FEC decoder (LDPC/BCH) may include a parityde-puncturing & infinite LLR insertion block, an LDPC decoding block anda zeros removal & BCH decoding block.

The apparatus for receiving broadcast signals according to the presentembodiment may independently process each of the PLS1 data and the PLS2data. Hereinafter, operations of the respective functional blocks willbe described.

As illustrated in FIG. 9, the synchronization & demodulation module 9000may receive input signals through m Rx antennas, perform signaldetection and synchronization with respect to a system corresponding tothe apparatus for receiving broadcast signals and carry out demodulationcorresponding to a reverse procedure of the procedure performed by theapparatus for transmitting broadcast signals.

The signaling decoding module 9400 may obtain PLS information from thesignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9100, demapping & decodingmodule 9200 and output processor 9300 may execute functions thereofusing the data output from the signaling decoding module 9400.

The constellation demapper may demap demodulated PLS data onto a softbit having a log likelihood ratio (LLR) in symbol units.

The bit deinterleaver may perform bit deinterleaving on the demapped PLSdata. The bit deinterleaver may perform a reverse procedure of thebit-interleaving block described above with reference to FIGS. 30 and33.

The shortened/punctured FEC decoder (LDPC/BCH) may perform FEC decodingon the bit-deinterleaved PLS data. As described in the foregoing, theshortened/punctured FEC decoder may include the parity de-puncturing &infinite LLR insertion block, the LDPC decoding block and the zerosremoval & BCH decoding block, and each of the blocks may process theinput bit-deinterleaved PLS data. Hereinafter, operations of therespective blocks included in the shortened/punctured FEC decoder willbe described.

The parity de-puncturing & infinite LLR insertion block may restoreparity bits punctured in the apparatus for transmitting broadcastsignals. In this case, the parity de-puncturing & infinite LLR insertionblock may perform de-puncturing by inserting parity bits into positionswhere the parity bits are located before being punctured in theapparatus for transmitting broadcast signals.

The parity de-puncturing & infinite LLR insertion block may restore zerobits removed in an operation processed in the apparatus for transmittingbroadcast signals. In this case, the parity de-puncturing & infinite LLRinsertion block may insert 0 bit having an LLR.

The LDPC decoding block may perform LDPC decoding on the PLS datasubjected to the parity de-puncturing & infinite LLR insertion block.When the PLS data received by the apparatus for receiving broadcastsignals is QC-LDPC-encoded PLS data, the LDPC decoding block may performparallel decoding on the PLS data in units of QC sizes.

Thereafter, the zeros removal & BCH decoding block may extract aninformation part from the LDPC-decoded PLS data. The zeros removal & BCHdecoding block may perform BCH decoding after deleting zero bits whichare inserted into the extracted information part.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 37 illustrates a BICM block for protection of physical layersignaling (PLS), emergency alert channel (EAC) and fast informationchannel (FIC). EAC is a part of a frame that carries EAS informationdata and FIC is a logical channel in a frame that carries the mappinginformation between a service and the corresponding base DP.

The BICM block for protection of PLS, EAC and FIC according to thepresent embodiment may include a PLS FEC encoder, a bit interleaver anda constellation mapper. Operations of the respective blocks are the sameas those described with reference to FIG. 6.

Hereinafter, a detailed configuration and operation of the bitinterleaver will be described.

As illustrated in FIG. 37, the bit interleaver according to the presentembodiment may include a block interleaver and a bit demux. Asillustrated with reference to FIG. 34, the bit demux block maydemultiplex PLS data to which a QAM order of 16-QAM or more is applied.

The block interleaver may perform the same operation as that of the bitinterleaver described above with reference to FIGS. 30 to 33. The bitdemux may perform the same operation as that of the bit demux describedabove with reference to FIG. 34.

Above-described blocks may process emergency alert channel (EAC) andfast information channel (FIC). The procedure of processing the EAC andFIC may be the same as that of the PLS data as above-described.Otherwise, the procedure of processing the EAC and FIC may differ fromthat of the PLS data as above-described.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 38 illustrates input and output data of the bit interleaveraccording to the present embodiment.

FIG. 38 illustrates input and output data of the bit interleaver for16-QAM.

FIG. 38(a) illustrates data input to the bit interleaver. The data inputto the bit interleaver is LDPC encoded data.

FIG. 38(b) schematically illustrates a write operation and a readingoperation of the bit interleaver.

The LDPC-encoded PLS data illustrated in FIG. 38(a) has the sameconfiguration as that of the LDPC-encoded PLS data described above withreference to FIG. 32(a).

A whole codeword refers to LDPC-encoded bits of the PLS data. Inaddition, information parts and parity parts correspond to LDPC info(Kldpc) and LDPC parity (Nldpc−Kldpc), respectively, of FIG. 32(a). Thewhole codeword according to the present embodiment may have a lengthequal to a value of Nldpc of Table 4. The whole codeword in the presentspecification may be referred to as an LDPC codeword or a codeword.

FIG. 38 corresponds to an example of the operation of the bitinterleaver for 16-QAM. Thus, the number of columns illustrated in FIG.38(b), that is, a QAM-order is 4. Therefore, the LDPC-encoded PLS dataillustrated in FIG. 38(a) is divided into four equal parts and writtento each of the columns. Each of two arrows below the information partsand the parity parts has a length corresponding to half of a length ofthe whole codeword. Each of two arrows below the first arrow, which isone of the two arrows below the information parts and the parity parts,has a length corresponding to ¼ the length of the whole codeword. Thebit interleaver may write bits corresponding to the length of one of thearrows on the bottom to each column in a column-wise manner.

In the read operation, the bits for one constellation symbol are readout sequentially row-wise and fed into the bit demultiplexer block.These operations are continued until the end of the column.

In this case, each QAM symbol may include an information bit of at least1 bit.

FIG. 39 illustrates a configuration of a bit interleaver block of abroadcast signal transmission apparatus according to an embodiment ofthe present invention.

Specifically, FIG. 39 illustrates an equivalent configuration of the bitinterleaver block described with reference to FIG. 33(a). An operationand effect of the bit interleaver block illustrated in FIG. 39 may bethe same as an operation and effect of the bit interleaver blockillustrated in FIG. 33(a).

As illustrated in FIG. 33, the bit interleaver block according to theembodiment of the present invention may include the LDPC encoder, thecyclic shift block, and the QPSK mapper. In addition, as illustrated inFIG. 39, the bit interleaver block according to the present embodimentmay include an LDPC encoder, a BPSK mapper, a cyclic shift block, and acomplex mapper. The configuration of the bit interleaver blockillustrated in FIG. 39 is an equivalent configuration of the bitinterleaving block illustrated in FIG. 33.

A mapper included in the bit interleaver block according to anembodiment of the present invention may be referred to as a QPSK mapper,a BPSK mapper, or a complex mapper, and the mapper may disperseFEC-encoded bits to a real part and an imaginary part. The complexmapper according to the present embodiment may correspond to the QPSKmapper or the BPSK mapper, and a specific name of the mapper may bechanged by a designer.

A signaling generation block according to an embodiment of the presentinvention may perform a bit interleaving operation and/or a blockinterleaving operation according to a modulation order. When themodulation order corresponds to QPSK, the bit interleaving operationaccording to the present embodiment may be performed based on an SSDscheme. Therefore, the configurations of the bit interleaver blocksillustrated in FIGS. 33 and 39 may be applied when the modulation ordercorresponds to QPSK and the SSD scheme is employed.

When the modulation order corresponds to QPSK or higher order QAMgreater than or equal to QPSK, block interleaving may be performed basedon a QAM order. In this case, a block interleaving operation may be thesame as the above-described bit interleaving operation illustrated inFIG. 33(b). The block interleaving operation and effects thereofaccording to the present embodiment are the same as the abovedescription with reference to FIG. 33(b).

Hereinafter, a description will be given of a specific operation of bitinterleaving performed based on the SSD scheme when the modulation ordercorresponds to QPSK.

The mapper according to the present embodiment may duplicate an outputbit of the LDPC encoder in the real part and the imaginary part.Specifically, the mapper according to the present embodiment maydisperse respective output bits of the LDPC encoder to the real part andthe imaginary part, thereby acquiring I/Q diversity gain. In this case,the mapper may equally allocate LDPC information bits and parity bits toQAM symbols (or QPSK symbols). Therefore, even when any one of symbolsis nulled by a transmission channel environment, information bits arenot continuously mapped to one QAM symbol. Thus, it is possible toprevent information bits corresponding to 2 or more bits from beingsimultaneously nulled. In this case, performance on a fading channel maybe enhanced while maintaining performance in an AWGN environment.

A cyclic shift memory of the cyclic shift block according to the presentembodiment may perform an interleaving operation. The cyclic shiftmemory according to the present embodiment may be connected to an inputend of the imaginary part of the mapper as illustrated in FIG. 33 orFIG. 39, and connected to an input end of the real part of the mapperalthough not illustrated.

FIG. 40 shows an equation indicating an operation of a bit demultiplexerof a broadcast signal transmission apparatus according to an embodimentof the present invention.

Specifically, FIG. 40 expresses a higher-QAM demultiplexing rule by anequation, which is similar to the above-described equation of FIG.34(b).

Hereinafter, the higher QAM demultiplexing rule illustrated in FIG. 40is similar to the above description with reference to FIG. 34(b) exceptfor c_(i)(η_(MOD)−1)=b_(i)((i+η_(MOD)−1)% η_(MOD)), and thus a specificdescription thereof will be omitted. The bit demultiplexer according tothe present embodiment may perform the operation of FIG. 34(a) based onthe equation of FIG. 40.

The bit demultiplexer according to the present embodiment may not beoperated under a particular condition. The particular condition may bechanged according to modulation order or encoding scheme. Specifically,the particular condition may correspond to a case of QPSK to which theSSD encoding scheme is applied or a case in which the modulation orderis QPSK. When the bit demultiplexer is not operated, a bit may bedirectly mapped to a QAM symbol.

FIG. 41 illustrates a bit deinterleaver of a broadcast signal receptionapparatus according to an embodiment of the present invention.Specifically, the bit deinterleaver illustrated in FIG. 41 may performan operation corresponding to a reverse operation of the above-describedoperation of the bit interleaver according to the embodiment of thepresent invention.

The broadcast signal reception apparatus according to the presentembodiment may perform the operation of decoding PLS data described withreference to FIG. 36 when a modulation order is QPSK, and a broadcastsignal that includes PLS data processed based on SSD encoding is notreceived. Therefore, the bit deinterleaver illustrated in FIG. 41 mayoperate only when the modulation order is QPSK, and the broadcast signalreception apparatus according to the present embodiment receives thebroadcast signal that includes PLS data processed based on SSD encoding.

When the modulation order is QPSK, and the broadcast signal thatincludes PLS data processed based on SSD encoding is not received, thebit deinterleaver according to the present embodiment may differentlyoperate based on a dimension of LLR decoding as illustrated in FIG. 41.

FIG. 41(a) illustrates a configuration corresponding to a case in whichthe bit deinterleaver according to the present embodiment performs2D-LLR decoding and an equation of an output bit of a 2D-QPSK demapper.The bit deinterleaver illustrated in FIG. 41(a) may operate uponreceiving PLS data undergoing the bit interleaving operation describedwith reference to FIG. 33(a) and FIG. 39, and acquire maximum decodingability using a 2D-LLR demapper (or 2D-LLR QPSK demapper). In this case,the bit deinterleaver according to the present embodiment may include adelay line block, a cyclic shift block, a 2D-QPSK demapper, and ashortened/punctured FEC decoder block. Hereinafter, a description willbe given of specific data processing operations of the respectiveblocks.

The bit deinterleaver according to the present embodiment may perform anoperation corresponding to a reverse operation of the cyclic shift blockmemory described with reference to FIG. 33(a) and FIG. 39 on a QPSKsymbol including input PLS data.

Therefore, the QPSK symbol including PLS data may be input to each ofthe delay line block and the cyclic shift block. Thereafter, the delayline block may output a value corresponding to an I component, and thecyclic shift block may output a value corresponding to a Q component.Thereafter, the 2D-QPSK demapper applies the values of the I and Qcomponents to the equation at the bottom of FIG. 41(a), therebyoutputting LLR(bi)

Parameters included in the equation for obtaining LLR(bi) have meaningsas below.

Ix and Qx denote values of I and Q components of each QPSK symbol, andeach of ρI and ρQ denotes amplitude—fading factor of I and Q.

FIG. 41(b) illustrates a configuration corresponding to a case in whichthe bit deinterleaver according to the present embodiment performs1D-LLR decoding. In this case, the bit deinterleaver according to thepresent embodiment may include a 1D-QPSK demapper, a delay line block, acyclic shift block, and a shortened/punctured FEC decoder block. In thiscase, a QPSK symbol including PLS data may be first input to the ID-QPSKdemapper. The 1D-QPSK demapper according to the present embodiment maysoftly combine LLR values based on information indicating that a realpart and a cyclic shifted imaginary part are repeated. Therefore, whenthe bit deinterleaver according to the present embodiment operates basedon a 1D-QPSK demapping scheme, there is no need to use the equation foroutputting specific LLR(bi) which is necessary when the 2D-QPSK demapperis used as in FIG. 41(a). Therefore, it is possible to expect lowercomplexity of the broadcast signal reception apparatus according to thepresent embodiment.

A specific operation of a block excluded from the above descriptionamong specific blocks included in the bit deinterleaver of FIG. 41(b)may be the same as an operation of a specific block having the same nameincluded in the bit deinterleaver of FIG. 41(a).

FIG. 42 shows an equation indicating an operation of a bit demultiplexerof a broadcast signal transmission apparatus according to an embodimentof the present invention.

Specifically, FIG. 42 shows another equation indicating the operation ofthe bit demultiplexer described with reference to FIG. 34. The operationof the bit demultiplexer described with reference to FIG. 34(a) may beperformed based on the equation shown in FIG. 42. Specific definitionsof parameters of the equation are similar to the above description withreference to FIG. 34.

The operation of the bit demultiplexer according to the presentembodiment described with reference to FIGS. 34 and 42 has effects andcharacteristics as below.

LDPC output of PLS data according to an embodiment of the presentinvention has a reliability that may vary according to the amount ofsignaling data, and thus an existing bit demultiplexing scheme performedaccording to a fixed rule is not suitable. The existing bitdemultiplexing scheme performed according to the fixed rule may be ascheme that demultiplexes a data stream into sub-streams based on apredetermined table or parameter value as in standards such as DVB-T,DVB-NGH, etc.

The amount of signaling data according to the present embodiment mayvary according to a service providing environment of a service provider.In this regard, the broadcast signal transmission apparatus according tothe present embodiment may provide a constant SNR-threshold byprocessing variable signaling data using the above-described bitdemultiplexing scheme. In the bit demultiplexing scheme according to thepresent embodiment, there is no need to separately define ashortening/puncturing order according to a modulation order. Therefore,the broadcast signal transmission apparatus according to the presentembodiment may perform bit demultiplexing based on the sameshortening/puncturing order defined irrespective of a modulation value.

FIG. 43 shows applicable ModCod combinations when PLS data signalingprotection according to an embodiment of the present invention isperformed.

PLS data signaling protection according to an embodiment of the presentinvention described with reference to FIGS. 30 to 32 may be performedbased on a protection level to be described below. PLS data signalingprotection according to the present embodiment to be described below maybe performed according to a ModCod value categorized based on throughputof service data or signaling data. A category according to an embodimentof the present invention may be referred to as a mode or an informationmode.

A trade-off exists between protection level (or robustness) andefficiency. In other words, as the protection level increases,redundancy increases, and thus data throughput may decrease.

Therefore, when signaling protection is performed based on an LDPCencoding scheme, it is important to adequately adjust the protectionlevel.

FIG. 43(a) is a table showing an applicable ModCod combination when alength of LDPC code is 64 k.

In the table, a row indicates code rates and a column indicatesmodulation values. A code rate is expressed by x/15, in which x may haveany one of values of 2 to 13. A modulation value may correspond to anyone of 2, 4, 6, 8, 10, and 12. The table of FIG. 43(a) shows datathroughput according to a combination of each code rate and eachmodulation value.

FIG. 43(b) is a table showing an applicable ModCod combination when alength of LDPC code is 16 k.

The table has the same structure as that of FIG. 43(a), and a modulationvalue may correspond to any one of 2, 4, 6, and 8.

As described in the foregoing, a result value of the tables shown inFIGS. 43(a) and 43(b) indicates data throughput according to a ModCodcombination. The number of significant ModCod combinations is 46 whenthe length of LDPC code is 64 k, and the number of significant ModCodcombinations is 27 when the length of LDPC code is 16 k.

Therefore, the broadcast signal transmission apparatus according to thepresent embodiment may process signaling data by categorizing 73significant ModCod combinations according to a particular rule based onthe tables of FIG. 43. When signaling protection is performed in thisway, it is possible to expect further enhanced performance in terms ofrobustness and efficiency.

FIGS. 44 to 46 are tables that categorize and show data according todata throughput. Specifically, in FIGS. 44 to 46, applicable ModCodcombinations are categorized based on data throughput shown in theabove-described tables of FIG. 43. Data throughput shown in FIGS. 44 to46 is related to each of a case in which a BCH operation is included(with BCH or w/BCH) and a case in which the BCH operation is notincluded (without BCH or w/o BCH).

A length of LDPC code, a modulation order (Mod), a code rate (numeratorfor CR), SNR (FER-10^−4, AWGN), SNR (FER-10^−4, Ray), and datathroughput according to whether the BCH operation is included(throughput (w/BCH), throughput (w/o BCH)) are shown at the tops ofFIGS. 44 to 46.

Data may be classified into five categories in total including aninterval in which data throughput is greater than 0 and less than orequal to 1 (category 1), an interval in which data throughput is greaterthan 1 and less than or equal to 2 (category 2), an interval in whichdata throughput is greater than 2 and less than or equal to 3.5(category 3), an interval in which data throughput is greater than 3.5and less than or equal to 5.5 (category 4), and an interval in whichdata throughput is greater than 5.5 (category 5).

The number of classified categories and a criterion for classifyingcategories may be changed by a designer. According to an embodiment ofthe present invention, the number of classified categories may be 7, andthe criterion for classifying categories may be an information length ofLDPC code.

FIG. 47 is a table showing BICM ModCod performance for each categoryaccording to an embodiment of the present invention.

Specifically, FIG. 47 is a table obtained based on result values of thetables shown in FIGS. 44 to 46. Data-BICM ModCod Performance on the leftside of FIG. 47 shows maximum capacity (or maximum data throughput), aminimum AWGN value, and a minimum Rayleigh value for each category.Signaling ModCod on the right side of FIG. 47 shows a ModCod valueapplied to each category.

FIG. 48 is a table showing BICM ModCod for each category according to anembodiment of the present invention. Specifically, FIG. 48 correspondsto another example of FIG. 47 and proposes a more suitable ModCodcombination when targeted performance varies for each particularcategory.

Data may be classified into six categories based on data throughput. Inthis case, intervals may be more uniform when compared to a case inwhich data is classified into five categories. Signaling ModCod on theright side of FIG. 48 shows a ModCod value applicable to each categorywhen robustness of data is mainly targeted in Category 1 and Category 2and data transmission (high capacity) is mainly targeted in Category 3to Category 6.

FIG. 49 is a conceptual diagram illustrating a broadcast signaltransmission apparatus and a broadcast signal reception apparatusaccording to an embodiment of the present invention operating based onModCod information.

Specifically, the broadcast signal transmission apparatus and thebroadcast signal reception apparatus according to the present embodimentmay have the same configurations as those of the broadcast signaltransmission apparatus of FIG. 30 and the broadcast signal receptionapparatus of FIG. 36.

The broadcast signal transmission apparatus according to the presentembodiment may transmit a category value as level (or category)information of signaling data. For example, level information ofsignaling data may be transmitted such that “000” is transmitted forcategory1, “001” is transmitted for category2, “010” is transmitted forcategory3, “011” is transmitted for category4, and “100” is transmittedfor category5. In this case, the broadcast signal reception apparatusaccording to the present embodiment may acquire information about acorresponding category by decoding level information of data. Thebroadcast signal reception apparatus according to the present embodimentmay perform FEC decoding by acquiring ModCod information based oncategory information of data.

Alternatively, the broadcast signal transmission apparatus according tothe present embodiment may transmit level (or category) information ofdata by including a ModCod value as the information in signalinginformation. The broadcast signal transmission apparatus according tothe present embodiment may determine a ModCod value after classifyingdata into categories. For example, among code rate values, 3/15 LDPC maybe signaled as Code_type=“00” and 6/15 LDPC may be signaled asCode_type=“01”. A modulation value may be signaled as “000” in BPSK,“001” in QPSK, “010” in 16QAM, “011” in 64QAM, and “100” in 256QAM.

Therefore, if signaling data is classified as Category 3 when thebroadcast signal transmission apparatus according to the presentembodiment performs signaling based on the table of FIG. 48,Code_type=“01” and Mod_type=“001” may be signaled. In this case, thebroadcast signal reception apparatus according to the present embodimentmay decode signaling data by acquiring information of Code_type andMod_type.

The broadcast signal transmission apparatus according to the presentembodiment may perform signaling by arbitrarily changing a category ofdata to enhance robustness. For example, data, data throughput(capacity) of which is 7.2, corresponds to Category5. In this case, thebroadcast signal transmission apparatus according to the presentembodiment may determine a ModCod value to be 6/15-LDPC and 256QAM basedon the table of FIG. 47. However, the broadcast signal transmissionapparatus according to the present embodiment may determine the ModCodvalue to be 6/15-LDPC and 64QAM corresponding to Category4 to enhancerobustness of data.

The broadcast signal transmission apparatus according to the presentembodiment may include the ModCod value or the category value describedabove as signaling information in a PLS or a bootstrap and transmit thevalue. In addition, the broadcast signal transmission apparatusaccording to the present embodiment may protect signaling informationbased on a ModCod value determined for each category. The broadcastsignal reception apparatus according to the present embodiment mayperform signaling decoding based on bootstrapping, a PLS, a ModCod valueincluded in L1 signaling data, or category information.

Names of a PLS, PLS1, and PLS2 according to an embodiment of the presentinvention may be changed to L1 signaling data, L1-static data (or L1pre-data), and L1-dynamic data (or L1 post-data), respectively.

FIG. 50 illustrates a configuration of a decoding block of L1 signalingdata of a broadcast signal reception apparatus according to anembodiment of the present invention.

FIG. 50 corresponds to another example of the PLS data decoding block ofthe broadcast signal reception apparatus according to the embodiment ofthe present invention described with reference to FIG. 36. Therefore, adetailed description of an operation of a block, among blocks shown inFIG. 50, which overlaps with a block of FIG. 36 will be omitted.

The decoding block of the L1 signaling data according to the presentembodiment may include a cell demapper, a bit deinterleaver, an LLRmerging block, an infinite (Inf) LLR insertion block, a zero LLR paddingblock, a parity de-permutation block, an LDPC decoding block, a zeroremoving block, a BCH decoding block, a descrambling block, and a datamerging block. Sub-blocks that may be included in the decoding block ofthe L1 signaling data according to the present embodiment may be omittedor added by a designer.

The cell demapper according to the present embodiment may demap an L1signaling data cell included in a signal frame. The L1 signaling datacell may include an L1 static cell and an L1 dynamic cell. The L1signaling data decoding according to the present embodiment may beapplied to each of L1 static data and L1 dynamic data. In this case, thesame decoding process may be applied except for the data merging block.The L1 dynamic data may be split into a plurality of FEC blocks at atransmitting end, and then FEC-encoded and transmitted. Therefore, thedata merging block according to the present embodiment may merge onlythe L1 dynamic data.

Thereafter, a constellation demapper may receive a cell output from thecell demapper, and demap the cell to a bit based on a constellation ofeach cell. Thereafter, the constellation demapper may output the bit ina form of LLR. The bit deinterleaver may perform a reverse operation ofthe above-described L1 bit interleaver. In other words, the bitdeinterleaver according to the present embodiment may align bits usingan FEC block as a unit.

When a repetition mode is applied to protection of the L1 signaling datain a transmitter, the LLR merging block may merge LLRs of repeatedlytransmitted L1 signaling bits in an FEC block. The repetition modeaccording to the present embodiment may indicate that L1 data istransmitted by being repeatedly included in the same signal frame ordifferent signal frames. Alternatively, the repetition mode according tothe present embodiment may indicate that some parity bits of L1 data areoverlapped and transmitted. The two cases are intended to enhancerobustness when a signal frame is transmitted. The Inf LLR insertionblock may allocate an LLR to a bit having high reliability among bitsshortened in an L1 encoding process. Even though a bit shortened in anLDPC encoding process is not actually received by a receiver, the bitcorresponds to data known to the receiver as a value of 0. Therefore, asdescribed in the foregoing, bits having reliable LLRs may be allocatedto an information part. On the other hand, an LDPC puncturing bit is nottransmitted after LDPC encoding, and thus the zero LLR padding block mayinsert zero-LLR into a position of a parity bit to indicate that thecorresponding bit cannot be determined to be 0 or 1. The parityde-permutation block may perform an operation corresponding to a reverseoperation of L1 parity permutation. The parity de-permutation block mayoutput LLRs corresponding to a length of an LDPC codeword. Thereafter,the LDPC decoding block may perform LDPC decoding of the LLRscorresponding to the length of the LDPC codeword to output an LDPCinformation part in bits.

Thereafter, the zero removing block may remove zero bits correspondingto an L1 zero insertion interval. Thereafter, the L1 signaling data maybe BCH-decoded and descrambled.

Information necessary when the L1 signaling data is decoded may be fixedto a system parameter. Examples of the information necessary when the L1signaling data is decoded may include information related to aconstellation applied to the L1 signaling data, information related to arepetition mode, length information of the L1 signaling data, andinformation related to the number of punctured LDPC parity bits. Inaddition, in a broadcast network using a heterogeneous system,information necessary to decode the L1 signaling data may be transmittedby being included in a preamble or a bootstrap.

FIG. 51 is a flowchart illustrating a method of transmitting a broadcastsignal according to an embodiment of the present invention.

In S51000, a broadcast signal transmission apparatus according to anembodiment of the present invention may encode data (or service data)that transmits at least one broadcast service component. As described inthe foregoing, the data according to the present embodiment may beprocessed for each DP corresponding to the data. The data may be encodedby the bit interleaved coding & modulation block 1010.

In S51010, the broadcast signal transmission apparatus according to thepresent embodiment may encode signaling data (which may be referred toas physical signaling data or PLS). As described in the foregoing, thesignaling data according to the present embodiment may include L1-staticdata and L1-dynamic data.

As described in the foregoing, a PLS, PLS1, and PLS2 according to anembodiment of the present invention may be referred to as signaling data(or L1 signaling data), L1-static data (or L1 pre-data), and L1-dynamicdata (or L1 post-data), respectively.

A broadcast signal reception apparatus according to an embodiment of thepresent invention may divide the L1-dynamic data into M blocks to encodethe L1-dynamic data to a codeword having a constant size of N.Thereafter, the broadcast signal transmission apparatus according to thepresent embodiment may BCH-encode each block, perform zero padding oneach BCH-encoded block, attach parity bits to a rear of the zero-paddedblock, and puncture the parity bits, thereby outputting an FEC block.

Specifically, the broadcast signal transmission apparatus according tothe present embodiment may successively insert zero-padding bits intoeach block according to a determined zero-padding sequential order atthe time of zero padding. Thereafter, the broadcast signal transmissionapparatus according to the present embodiment may permute thezero-padded block based on the zero-padding sequential order.Thereafter, the broadcast signal transmission apparatus according to thepresent embodiment may perform LDPC encoding by attaching parity bits toa rear of the permuted block, and perform parity bit interleaving.Thereafter, the broadcast signal transmission apparatus according to thepresent embodiment may delete the inserted zero-padding bits. Thebroadcast signal transmission apparatus according to the presentembodiment may be divided into a plurality of categories according to asize of the L1 signaling data. The broadcast signal transmissionapparatus according to the present embodiment may encode the L1signaling data based on a ModCod and a modulation value determinedaccording to the divided categories.

The broadcast signal transmission apparatus according to the presentembodiment may separately process (or encode) PLS1 and PLS2.Specifically, the broadcast signal transmission apparatus according tothe present embodiment may insert padding data before splitting PLS2. Inaddition, some parity bits included in LDPC-encoded PLS2 may bepunctured.

Thereafter, the broadcast signal transmission apparatus according to thepresent embodiment may permute LDPC parity bits included in PLS2 basedon a permutation order after puncturing. The broadcast signaltransmission apparatus according to the present embodiment may use apermutation order determined based on an LDPC code rate.

Thereafter, the broadcast signal transmission apparatus according to thepresent embodiment may select some of the punctured parity bits totransmit the selected parity bits by inserting the selected parity bitsinto PLS2. In this case, the selected parity bits may be referred to asadditional parity bits. PLS1 may include information about whether theadditional parity bits are included in PLS2. The additional parity bitsmay contribute to enhancement of decoding performance in the broadcastsignal reception apparatus.

The signaling data may be encoded by the PLS FEC encoder 6000 of thebroadcast signal transmission apparatus according to the presentembodiment.

Thereafter, in S51020, the broadcast signal transmission apparatusaccording to the present embodiment may create at least one signalframe. The signal frame according to the present embodiment may includesignaling data and service data. The signal frame may be created by theframe building block 1020.

Thereafter, in S51030, the broadcast signal transmission apparatusaccording to the present embodiment may modulate the at least onecreated signal frame using an OFDM scheme. OFDM modulation of the signalframe may be performed by the waveform generation module 1300.

Thereafter, in S51040, the broadcast signal transmission apparatusaccording to the present embodiment may transmit at least one broadcastsignal carrying the at least one created and modulated signal frame.

FIG. 52 is a flowchart illustrating a method of receiving a broadcastsignal according to an embodiment of the present invention.

FIG. 52 corresponds to a reverse process of the method of transmittingthe broadcast signal described with reference to FIG. 51.

In S52000, a broadcast signal reception apparatus according to anembodiment of the present invention may receive at least one broadcastsignal. The broadcast signal according to the present embodimentincludes at least one signal frame, and each signal frame may includesignaling data and service data.

In S52010, the broadcast signal reception apparatus according to thepresent embodiment may demodulate the at least one received broadcastsignal using an OFDM scheme. The broadcast signal may be demodulated bythe synchronization & demodulation module 9000.

Thereafter, in S52020, the broadcast signal reception apparatusaccording to the present embodiment may operate according to a reverseorder of the operation of the PLS FEC Encoder 6000 described above withreference to FIG. 28. Specifically, the broadcast signal receptionapparatus according to the present embodiment may LDPC-decode PLStransmission bits included in the signal frame, and then BCH-decode thebits. When the broadcast signal reception apparatus according to thepresent embodiment BCH-decode signaling data subjected to theabove-described PLS encoding scheme, the broadcast signal receptionapparatus may BCH-decode only signaling data excluding a zero-paddingbit. A broadcast signal transmission apparatus according to anembodiment of the present invention may be divided into a plurality ofcategories according to a size of L1 signaling data. The broadcastsignal transmission apparatus according to the present embodiment mayencode the L1 signaling data based on a ModCod and a modulation valuedetermined according to the divided categories.

The broadcast signal reception apparatus according to the presentembodiment may separately process (or decode) PLS1 and PLS2.Specifically, the broadcast signal reception apparatus according to thepresent embodiment may delete padding data included in PLS2. Inaddition, the broadcast signal reception apparatus may restore puncturedparity bits included in PLS2 at the time of LDPC decoding. In this case,inserted padding data and punctured parity bits may have sizesdetermined at a transmitting end by the above-described method orequation. Therefore, the broadcast signal reception apparatus accordingto the present embodiment may reversely obtain the padding data and thepunctured parity bits based on the above-described method or equation,or use the padding data and the punctured parity bits as known data.

As described in the foregoing, PLS2 may include additional parity bits,and PLS1 may include information about whether the additional paritybits are present. In addition, the above-described permutation order maybe used as known data when the broadcast signal reception apparatusperforms decoding.

PLS decoding may be performed by the signaling decoding module 9040.

Thereafter, in S52020, the broadcast signal reception apparatusaccording to the present embodiment may separate at least one signalframe from the demodulated broadcast signal. The signal frame may beseparated by the frame parsing module 9010.

Thereafter, in S52040, the broadcast signal reception apparatusaccording to the present embodiment may decode the service data carryingat least one broadcast service component. The data may be decoded by thedemapping & decoding module 9020.

It will be appreciated by those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

Both apparatus and method inventions are mentioned in this specificationand descriptions of both of the apparatus and method inventions may becomplementarily applicable to each other.

What is claimed is:
 1. A method for transmitting broadcast signals, themethod comprising: encoding, by an encoder, service data; encoding, by asignaling encoder, signaling data based on a mode of the signaling data,wherein the signaling data is categorized to one of plural modes basedon a modulation order for the signaling data; building, by a framebuilder, at least one signal frame including the encoded service data inat least one data symbol and the encoded signaling data in at least onesignaling symbol; modulating, by a modulator, data in the at least onesignal frame by an Orthogonal Frequency Division Multiplex (OFDM)scheme; and transmitting, by a transmitter, the broadcast signalscarrying the modulated data in the at least one signal frame, whereinthe broadcast signals further carry a bootstrap, wherein the bootstrapincludes category information indicating the mode of the signaling datain the at least one signaling symbol in the at least one signal frame,and wherein the category information represents that the modulationorder is one of 2, 4, 6 or
 8. 2. The method of claim 1, wherein theencoding of the signaling data includes: Forward Error Correction (FEC)encoding the signaling data; block interleaving the FEC encodedsignaling data; and demultiplexing the block interleaved signaling datausing a shifting method, wherein the shifting method is performed basedon the modulation order and an index of the signaling data.
 3. Themethod of claim 1, wherein the category information indicates a coderate of 3/15.
 4. The method of claim 2, wherein the shifting method isperformed when the modulation order is one of 4, 6 or
 8. 5. The methodof claim 2, wherein the block interleaving is performed by writing theFEC encoded signaling data into each of columns as column-wise, a numberof the columns depending on the modulation order, and reading bits ofthe written signaling data row-wise.
 6. An apparatus for transmittingbroadcast signals, the apparatus comprising: an encoder to encodeservice data; a signaling encoder to encode signaling data based on amode of the signaling data, wherein the signaling data is categorized toone of plural modes based on a modulation order for the signaling data;a frame builder to build at least one signal frame including the encodedservice data in at least one data symbol and the encoded signaling datain at least one signaling symbol; a modulator to modulate data in the atleast one signal frame by an Orthogonal Frequency Division Multiplex(OFDM) scheme; and a transmitter to transmit the broadcast signalscarrying the modulated data in the at least one modulated signal frame,wherein the broadcast signals further carry a bootstrap, wherein thebootstrap includes category information indicating the mode of thesignaling data in the at least one signaling symbol in the at least onesignal frame, and wherein the category information represents that themodulation order is one of 2, 4, 6 or
 8. 7. The apparatus of claim 6,wherein the signaling encoder includes: a Forward Error Correction (FEC)encoder to encode the signaling data by an FEC scheme; a blockinterleaver to interleave the FEC encoded signaling data by a blockinterleaving scheme; and a demultiplexer to demultiplex the blockinterleaved signaling data using a shifting method, wherein the shiftingmethod is performed based on the modulation order and an index of thesignaling data.
 8. The apparatus of claim 6, wherein the categoryinformation indicates a code rate of 3/15.
 9. The apparatus of claim 7,wherein the shifting method is performed when the modulation order isone of 4, 6 or
 8. 10. The apparatus of claim 7, wherein the blockinterleaver writes the FEC encoded signaling data into each of columnsas column-wise, a number of the columns depending on the modulationorder, and reads bits of the written signaling data row-wise.